Berlin-Melbourne Syzygy

Alcalá alight

2011-06-26T12:24:00.000+02:00

I'm now in Alcalá for EGC 2011. Last night I went out for stroll with my camera, sporting my new 'nifty fifty' 50mm f/1.8 lens. These are some shots I took.

New paper!

2011-06-24T20:20:00.000+02:00

A few days ago I uploaded a new paper onto the arXiv. It was written with Attila Pór, Pavel Valtr and David Wood. In it we consider the connectivity of visibility graphs, which are graphs drawn on point sets in the plane where two points are joined by an edge if they 'see' each other - i.e. there is no point on the line between them.

One of my favourite results in the paper is a lemma which says that if you have two properly coloured plane graphs drawn with straight edges which are separated by a line, you can add an edge between them which is also properly coloured. This is not true if they aren't separated by a line. It's one of those things which seemed like it had to be true, but was quite tricky to prove. In the end Attila found a tricky proof. Perhaps there is a short proof using something like Borsuk Ulam (wild guess) but we couldn't find it.

Berlin visits, past and future

2011-06-21T01:40:00.014+02:00

After my month in Lausanne last year I headed to Berlin again for about three weeks. That trip was self funded, but around that time I got the news that my supervisor and I had been successful in our application for some travel funding for a small cooperative project in Berlin and Melbourne. This will also allow me to visit again next year.

So now I am back in Berlin. I took the old MEL-DRW-SIN-FRA route with Jetstar on the first two legs, then Qantas. This was not so bad actually, especially since I got all the connections (I was on standby tickets) even though it was busy. Anyway, it's nice to be here again. My stay will last until mid August, with next week being spent in Spain at Los Encuentros de Geometría Computacional. I also hope to make a weekend trip to Belgium to see the 24hrs of Spa Francorchamps.

It was somewhat emotional last time seeing this city which I enjoy so much again after I had decided to move my studies back to Melbourne. Now I feel more relaxed because I know it will always be here, and I'll be back.

One of the first things I realised after getting here was that Melbourne maybe does have the edge food-wise (sorry Berliners!). About a week ago I had eaten at my favourite Indian restaurant in Melbourne, and when I arrived I went straight to one of my favourites here. I'm afraid it didn't compare well. At least eating out here is a lot cheaper than in Melbourne, especially with our high dollar.

On why one should be vegetarian and wear polyester shirts

2011-05-30T07:58:00.002+02:00

I was reading an article in the newspaper about world population, and then had a look at this interesting BBC program. It addresses the problem that our species is capabale of exponential reproduction, but the Earth contains a finite amount of resources, so eventually (in fact soon) we must hit those limits. Water is one of the most important resources. We all know about water restrictions in Melbourne, but our water use extends far beyond what we take from the taps. For example, a cup of coffee takes about 120L to produce, and a can of beer 150L. Wow, that's quite a lot you say, and I thought I was an eco-friendly occasional coffee and beer drinker. Well, if you're a vegetarian who wears mainly polyester you are doing your bit, at least in a relative sense, because a cotton shirt takes 3000L, and a hamburger a massive 8000L of water to produce! Even if you buy a cotton shirt but wear it many times, you might be excused, but assuming you only eat your burger once, well, shame on you!

Edit: From another source I read that a kilo of beef takes 16000L of water to produce, so this is fairly close to the estimate above. But, the same source (actually a vegan propaganda flyer) said that it takes 2000L to make a kilo of soy. I hadn't really thought about how much it might be, but for me this makes meat's water usage seem not quite as bad as I thought. Especially if you eat chicken instead of beef at a claimed usage of 4000L per kilo. Of course, there are many other reasons to be vegetarian apart from saving water.

RapNews

2011-05-24T05:26:00.000+02:00

RapNews is an awesome series of videos on YouTube from JuiceMedia describing current affairs with insightful and witty rhymes. I think these guys are amazing and their latest effort is one of the best.

Alfa AWUS036NH in Ubuntu 10.04

2011-04-15T15:05:00.001+02:00

Since upgrading to 10.04 (from 9.04) my super duper Alfa AWUS036NH high power usb wifi dongle stopped working. I found this post very helpful. The problem seems to be that there are now two drivers which conflict. Apparently the rt2870sta module is for normal use, while rt2800usb is for packet injection. Most of us don't want to do that, so the solution is to blacklist rt2800usb in /etc/modprobe.d/blacklist.conf and thus only use rt2870sta.

Note however that this particular card uses the Ralink rt3070 chipset. The rt2870sta driver works (it is presumably meant for the rt2870 chipset), but maybe there is a more appropriate driver floating around. You'd have to install it manually if it exists. I'm just happy that the card works (including with WPA2 security).

What if P=NP?

2011-04-01T04:35:00.056+02:00

Here is a nice (and tricky) problem that was posed in a computer science seminar that I am attending. It comes courtesy of Shir Peled.

Suppose you know that P=NP but don't know any polynomial time algorithms for NP-complete problems. Describe a polynomial time algorithm for SAT (or any NP-complete problem).

It may sound like a wierd question, but it does have a good answer. I will post the answer in a few days in case you want to try for yourself first.

Answer coming soon...

.
.
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So now for the answer. It turns out that this was an unintentional April fool's joke. I didn't state the problem exactly as I should have. To see why, let's look at the solution.

You start by enumerating all Turing machines as a list of strings which encode their behaviour. Since P=NP, somewhere in this list there is a polynomial time machine that solves your problem and prints out the certificate for yes instances of the problem in polynomial time. You then proceed as follows:

Run Machine 1 (M1) for its first step.
Run M2 for its first step, then M1 for its second step.
Run M3 for its first step, M2 for its second step, then M1 for its third step,
and so on.

After each step you run, if the machine halts, check (in polynomial time) if its output is a certificate for your instance. If your machine is the kth one in the list, its running time is p(n), and it takes q(n) steps to check a certificate, then this algorithm will find certificates for yes instances in time less than k^2 * p(n)^2 * q(n).

The problem arises when we consider what happens with no instances. Since there is no polynomial size certificate for non-membership of an NP language, we can't expect our machine to print one out. In fact, we know of no method in this case. The original question should have been:

Suppose you know that P=NP but don't know any polynomial time algorithms for NP-complete problems. Describe an algorithm for SAT (or any NP-complete problem) which accepts yes instances in polynomial time, and behaves arbitrarily on no instances.

Shir tells me the following regarding this problem:

This formulation is taken from Scott Aaronson's blog, and is presented in the last exercise here, although the legend I know claims it originally is an exam question that Ely Porat gave to his students.

Independent beer

2011-03-24T05:13:00.000+01:00

I was just reading about how Foster's goes about pricing their main beer labels, and how they give little chance to independent retailers. I can also imagine they and Lion Nathan aggressively acquire independent beer companies if they seem like becoming successful. So I wondered, how hard is it to buy beer from someone other than the big two? Perhaps it is like the case of soft drinks, where many apparently independent drink makers are just Coca-Cola Amatil in disguise. The following labels are not independent, though you might not have guessed:

Matilda Bay Brewing Co., makers of Beez Neez, and Fat Yak among others are wholly owned by Fosters.
Little Creatures, which sprang out of the sale of Matilda Bay, is publicly listed and 40% owned by Lion Nathan.
White Rabbit is owned by Little Creatures, hence 40% Lion Nathan.
James Squire and Boags are owned by Lion Nathan.
Cascade is owned by Fosters.
Bluetongue is owned by Coca-Cola Amatil and SABMiller.

If you really want to stick it to the man (and his marketing dept), fully independent breweries include:

Mountain Goat
Coopers (this surprised me!)
St Arnou

... and many more that you are less likely to find in the average pub.

HTC Legend WiFi connection

2011-02-07T04:11:00.001+01:00

Many people around the interwebs have complained about the WiFi connectivity of the HTC Legend. I certainly had some problems with mine, and would like to share some things that seem to have resolved them.

I have a Billion 7404VGPX router and my Legend is running standard Android 2.1-update1 Build2.10.178. My girlfriend's Legend is running the 2.2 firmware and has behaved exactly the same as mine.

Initially we found that the phones would connect ok if the router had been recently rebooted, but after a few hours or a day the connection would fail. If we tried to connect manually it would try for a second and then just say 'disconnected'.

There are many networks in my area (20-30 visible on some devices), so I thought maybe I needed to secure my router better. It was already running WPA2 Personal encryption. All I did was add MAC filtering and disable the SSID broadcast. This has made a huge difference - the phones now connect reliably days after the last router reset. I assume this added security has reduced the number of connection requests for the router and somehow this has made connecting easier. I have read some people suggest that it could help to move to a quieter channel if there are many networks around.

There are also people out there having bad reception even when they can connect. Our experience has been that the signal strength is not bad, and that it covers our small house well. When we had the initial problems the distance to the router did not seem to make any difference, so I don't think it was a signal strength issue.

Why Facebook sucks

2010-12-26T06:08:00.006+01:00

In no particular order:

1. Closedness

Facebook attempts to keep you inside Facebook and away from the rest of the interwebs. The purpose of the site is to sell advertising, so by keeping you there you'll see more ads. Of course you can link to outside pages and post content from outside, but the general plan is to keep you in the site. For example, you can't search the web from your facebook page.

2. Incompatibility

The messaging system is like email, but is not compatible with email. You can't access your messages from outside the site via IMAP for example. Feeds can't easily be exported in a standard format like RSS. This could easily be implemented, but would allow you to spend less time on the site, going against the aim of Closedness.

3. Featureless

Search functions are rudimentary and only allow you to search certain types of data (e.g. people), but not others (e.g. posts). The messaging system lacks the most basic functions of an email client. You can't forward your messages, set automatic replies, filter them, organise them in folders, etc.

4. Hidden history

What if you want to search back through the reams of crap on your wall or news feed? The data is still there, but it's difficult to access. You can't see how much old data is there, or quickly skip to any point in time. However it is still there, so someone may be able to dig it up in the future.

5. Inanity

More than most other communications media, Facebook is filled with pointless crap.

6. Insecurity

Facebook was not built with security in mind, and there have been various vulnerabilities discovered. You should not consider any data you upload as truly private.

7. Obscurity

The interface is not particularly clear or intuitive. Some features seem to be deliberately hidden, especially privacy settings, so that naive users are unaware of the options available to them.

8. Not customisable

You can't customise the look or layout of your own pages.

9. Monetised

You can buy extra apps to do obvious things that should be free (much the way Apple operates). These apps often have unfettered access to exactly the hard to get data mentioned above.

10. Looks

I'll let Fake Steve Jobs tell you about this one.

Compare these traits with offerings from Google, which are generally innovative, featureful, compatible with open standards, and interoperable with each other and the wider internet.

Julian Assange interviews

2010-12-23T02:29:00.002+01:00

A very calm interview on Al Jazeera by some old english guy called Frost.

And another from MSNBC where Assange gets a bit more aggressive, notably calling Mike Huckabee 'just another idiot' (9:45). Obviously he realises that on American television you have to speak up a bit to make yourself noticed behind the constantly changing graphics and tickers.

Visit msnbc.com for breaking news, world news, and news about the economy

Wikileaks Mirrors

2010-12-04T01:01:00.008+01:00

There now (24/12) seems to be over 1400 mirrors of wikileaks according to the official list of mirrors. However, be careful as some unscrupulous types may be using wikileaks' popularity to attract people to malware sites. Slashdot is a good source of information on what's going on.

This "information war" is extremely interesting and I imagine such conflicts will become more and more common. In abstract terms, I would guess that authorities will not be able to stop groups like wikileaks from disseminating information without really crippling the internet, to the extent that it would affect most other internet based services. The spread of information is much like entropy - it is essentially impossible to reverse once it has occurred. This may be demonstrated by wikileaks 'insurance' file which you can easily find on torrents. It is most likely an encrypted version of the archives which are slowly being released. If the key were divulged, the whole unedited archive would be available to anyone with the file.

Buying spanish guitars online: guitars.com.es and myspanishguitar.com

2010-11-18T04:20:00.002+01:00

Back when I was in Berlin I bought a beautiful Hermanos Sanchis Lopez Soleá from an online shop called guitars.com.es. This site is a sub-site of the larger spanish music site musicaltecla2.com which is based in Zaragoza. You can find an earlier post of mine about the guitar here.

It seems that guitars.com.es now redirects to myspanishguitar.com, but I'm pretty sure it's still the same people. I have just been looking around various forums and see that many people are asking if these sites are safe to deal with. Since I was very happy with their service I thought I'd relate my experience with them here.

Firstly, web design doesn't seem to be their strong point, so many people are put off by the crappy look of the website. The information on the site is not very complete, adding further to people's doubts. Also, their prices are often suspiciously low. This is partly explained by the fact that their prices don't include tax or shipping, and of course they are in Spain where the guitars are made.

All I can say is that I'm very sure that it's a legitimate business. If you are thinking of dealing with them I would begin by starting an email conversation with them about your needs. I found them extremely helpful.

Here is a post on a flamenco forum where I explained a bit about my experience with them. Briefly it went like this:

I enquired about the Alhambra 7Fc and Burguet 2F by email.
"Pedro" answered, and told me they had a Soleá on special for a bit higher than my budget (standard upsell). Pedro claimed he had chosen it at the factory himself for another buyer who later abandoned the deal.
I went to local Berlin guitar shops and tried various guitars including the 7Fc, the Soleá and some expensive Burguets though not the 2F.
The Soleá was clearly awesome and a big step above the 7Fc. I even liked it better than the Burguet ABF at twice the price.
After some bargaining Pedro offered me the Soleá for 1150 euro inc. case and shipping. The best price the berlin shop (www.justmusic.de) could do was 1250 w/o case.
I accepted Pedro's offer and sent the money by direct bank transfer. The new site seems to accept PayPal so this is probably less risky.
The guitar arrived as promised and in perfect condition. Since I had played the same model in the shop I am very sure it is not 'fake'. The story about the other buyer may or may not be true, though it did fit the general impression that they don't hold stock at their site, but rather get it when it is ordered.

You can find the full email conversation at the forum link I published above. If it disappears let me know and I will repost it here. It seems that someone on that forum appeared to be spruiking for the shop and pissed them off. I am just posting this to say that they may have agressive marketing tactics, but they do seem to be a legitimate business with good prices. As for buyer protection etc., I can't comment on those risks. I think they offer optional insurance.

The thing for overseas readers to remember is that Spanish guitars really are much cheaper in Spain. In 2001 I bought a new Alhambra 7P in Salamanca for AU$900 (I got a good deal) but its replacement cost in Australia for insurance purposes is $2,300 (or $2,690 here). So if you want to access this market you have to take the risks involved in international orders.

Edit: After direct contact with him, I'm now convinced that the apparent spruiker on the forum (Flamencofan) was in fact a legitimate satisfied customer.

DCG in Lausanne

2010-10-14T15:58:00.003+02:00

I spent the month of September in Lausanne so as to attend the special semester on Discrete and Computational Geometry at EPFL. There were two conferences during this period, one in the first week on DCG and the other in the last week on Geometric Graph Theory. Both were very interesting and had a great selection of speakers. This confirmed my conclusion after my trip to ICM India that it is best (mathematically) to go to more specific conferences. As well as hearing many interesting talks, between the two conferences I had the opportunity to meet lots of new people, and also begin a collaboration with my supervisor and some others.

Grammar, Statistics

2010-09-23T16:24:00.004+02:00

I've been doing a course on mathematical writing with my supervisor recently, so I am more alert than usual to bad grammar at the moment. Still this is inexcusable from The Age:

[There were some papers published recently about China and India.] They started with an article on Indian economic change in the RBA Bulletin, expanded by RBA assistant governor Philip Lowe's NatStats paper on the development of Asia and was rounded off last night at an Investec clients briefing with speeches by visiting Investec Asset Management strategist Michael Power and BHP's former China senior executive, Clinton Dines.

So a journalist got paid to write this sentence, and some other journalist got paid to edit it?!?

Further on in the article is a classic example of a vague and hence almost meaningless description of some economic data:

[The contribution of exports] to China's growth over the past decade has averaged just 1.5 per cent.

What does it mean that something 'contributed just 1.5% to China's growth' in the last decade? This could be interpreted in at least two ways: (1) That (in an average year) the change in export income was 1.5% of the total change in GDP. (2) That the change in export income was 1.5% out of a 9% (for example) total change in GDP - that is, it made up one sixth of the change. While (1) would be the most sensible calculation, it's not clear to me which one he means. There are still more, perhaps less plausible, interpretations: (3) The total export income was equal to 1.5% of the change in GDP. (4) The total export income was to the GDP growth as 1.5 is to 9 (say). These last two would be quite silly, so I would assume he didn't mean them, but since he doesn't explicitly say 'export growth' it's hard to tell.

The rest of the article is actually reasonably interesting, though not very well written.

Global Warmers and the fate of humanity

2010-09-14T19:50:00.007+02:00

I am often dismayed, in this time of increasing awareness of the negative effects of human activity on the planet, that the popularity of patio heaters (or 'global warmers' as my brother dubs them) is steadily rising. I can't remember seeing them say 10 years ago, but they are ubiquitous now. If people are at all interested in reducing their carbon emissions, how can they even contemplate burning gas to heat the outdoors. It's so patently stupid I can't be bothered thinking of an analogy for how stupid it is. The worst case is when you walk past a café with empty tables inside but people sitting outside under the global warmers. Actually no, there is the even worse case of a café with nobody inside or out, but still the warmers running to try to attract patrons. I see this often on Lygon St.

I know that cafés and bars can attract more patrons with them, because by and large people don't give a toss. I can understand hoteliers saying they can't not have them because they will lose all their patrons. So this is a perfect example of where we should just ban them. Then everyone would be even again, and the ridiculous waste of our resources would be avoided. I was heartened to find that the progressive Europeans have actually considered such a ban. Maybe we'll get there eventually. By the way, if it inconveniences smokers not to have a warm place to smoke outside, then good. I guess the rise in popularity of global warmers may have something to do with indoor smoking bans coming into effect.

RIP Silver Bullet

2010-09-12T12:32:00.001+02:00

I have just heard from dad that our 1980 Civic has finally gone to meet its maker. Given to us by my uncle, this was the first car I drove to uni in, and I shared it with my brother for 9 years. Over that time it was involved in many motorkhanas and a few autocross events (as pictured above), and my brother drove it to a class title in our club motorkhana championship. I learned a lot working on this car, including completely rebuilding an engine for it. Sadly rust got the better of the chassis and we had to admit that it was not safe (or clean) enough for everyday use. Due to space limitations we couldn't keep it just for motorkhana, so it's been sent to the scrap yard.

University funding in Australia

2010-09-09T20:16:00.005+02:00

Various factors have recently led to a large drop in international student enrolments at Australian universities. These factors include the global recession, changes to immigration rules, and the perceived threat of racial violence. In fact I can report that during my recent trip to India I was asked various times about this last issue, so it is certainly prominent in peoples perceptions there.

Under the current funding model for our universities, this drop in enrolments is a serious problem. The recent OECD report Education at a Glance shows that the level of public funding for tertiary education (44%) is well below the OECD average (69%). As one would guess, the US is even lower at 32%, but there is a telling difference. The report breaks the private funding into 'Household expenditure' (presumably funds raised from the students) and 'other private sources' (probably private companies in general). In the case of the US, roughly a third of funding comes from each of these categories - public, student fees and private entities. However in Australia only 18% comes from private entities, and 38% from households.

As mentioned, both the US and Australia (and the UK incidentally) are well below the OECD average for public funding. One figure sums this up: the EU average is 79% public funding for tertiary education. This is supported by my experience that in general university education in continental Europe is essentially free. Free university education existed in Australia not so long ago, and is not so hard to imagine given that primary and secondary education is more or less free. I often say to people that this difference between Europe and Australia can be understood when you consider that a highly skilled workforce is an essential asset in technically advanced economies like that of Germany, whereas our economy is based mostly on exploitation of mineral resources.

To return to the point of this post, one can understand from these numbers that student fees are important for Australian universities, and a large proportion of these fees are raised from international students. In fact Australia has the highest percentage of international students in the world at over 20% (and these students constitute almost 7% of all international students!). International students come to Australia for various reasons, but I'm not sure the absolute quality of the programs is the main one. Certainly prominent among their reasons are the fact that they can get a qualification in English, and also that it can be a path to permanent residency in Australia.

Unsurprisingly, they tend to choose vocational degrees, and often deliberately target the desirable qualifications as stipulated by the immigration policy at the time. Herein lies the problem in my opinion. The dependence of universities on income from foreign students skews their priorities away from traditional areas of intellectual endeavour and towards whatever modern courses happen to be popular. This means humanities departments especially, but also science faculties are under constant financial pressure, and are slowly dying in many cases. Without bothering to check which courses are in demand for potential immigrants, let me give you a case in point. In undergrad I had an Indonesian friend who had brilliant results in his math degree. At the end of his degree he was essentially deported because his degree was not 'valuable' enough. He considered doing a postgraduate course in accounting to build up enough 'points' to be able to stay. This is an obscene and disgraceful state of affairs. There is no better way to enrage a mathematician than to tell him he is less valued than an accountant!

Before you think that this is a veiled rant against immigration let me say what I would like to see change. I have no problem with international students coming to Australia to learn whatever they like, with or without the intention of staying here. It is also fair that they pay for their courses. However, this should not weaken the status of our leading universities as centres of learning and enquiry at the forefront of human endeavour (at least within Australia). The way to prevent this is to recognise the importance of strong universities and provide proper public funding more in line with European levels. Also if we readjusted the immigration rules our research centres could benefit from the many brilliant international students who, like my friend, would prefer to study something 'serious' if given the choice. Now for the sake of honesty I should mention another important statistic from the OECD report. The actual public spending on tertiary education as a percentage of GDP in Australia is in line with the OECD average at about 3%. (It just goes to show you should never trust a statistician.) This means that in some sense the extra money from international students comes on top of the typical public funding, but there are many countries which spend a much larger fraction than us, including Canada at 4.5% and New Zealand at 5.2%.

Quite frankly there are many courses taught at Australian universities which belong in technical colleges and other such institutions. These are often the courses with high international student enrolments so there is an incentive for leading universities to offer them. There is a further factor causing universities to offer these vocational courses. This is the trend that everyone (local or international) wants a degree from a 'University' regardless of whether they study a course that belongs at one. This has led to the phenomenon of many technical institutes being rebadged as universities. But in this sense names are not important. What would be nice is if the Group of Eight could concentrate on doing what they should be doing and leave other training to other institutions, whatever they are called. This increased focus would lead to increased prestige and the accompanying benefits to their research programs. After all, once we finish digging up Western Australia we better have learned how to do something else.

ICM 2010 - India

2010-09-08T22:15:00.000+02:00

It's been about two weeks since the International Congress of Maths finished in Hyderabad, India, so I should probably write something about it before I forget too much.

I guess it's important to separate the mathematical aspects from the mundane details of the organisation and the host city and so on. So on the mathematical side I can say that it was more or less as I expected. There were good talks and bad talks, certainly many famous speakers, but such a diverse range of topics that it was difficult to learn much. This was to be expected - I have heard people say that typically the bigger and more general a conference the worse it is, and this seems about right.

In the mornings there were plenary sessions, with a few good talks like those by Daniel Spielman and Cedric Villani, but mostly technical ones that I had no hope of learning much from. In the afternoons there were parallel sessions of invited talks grouped by topic, with a combinatorics session every second day or so. Several of these talks were good, and most were a lot more intelligible to me than the plenary talks. I particularly liked Henry Cohn's talk on the origins of symmetry (to quote a Muse album name).

As for the contributed talks, the standard was extremely inconsistent. There seems to have been no real selection process since, for example, on one particular day there were two talks giving short proofs of Fermat's last theorem. The first presenter was from the Triumphant Institute of Management Education, somewhere in India, and the second from Fairfax Media, Australia (oh the shame). I was fortunate enough to squeeze into the tiny seminar room for the first one, and saw basically what you would expect.

So much for the maths. On the social side I can say I had a fun time hanging out with my friends Lashi and Moritz. There were a few good times to be had like a day spent touring Hyderabad, and most notably a night partying with a group of grad students and one Fields Medalist.

As for organisation, I guess I expected it to be better given the fact that our $200 student conference fee ($400 for others) should have bought a lot in India. The conference dinner was average, and not held at a big enough venue, so that it was more like a fight to get fed than an opportunity to socialise. The lunches provided were terrible, especially considering their alleged 200 rupee value (though it seems that at other ICMs food was not always provided). Every meal I bought outside the conference venue cost less that 100 rupees and was far superior. The shuttle bus service was generally a complete shambles, etc.

As for my impressions of India, I didn't really see much. I had a nice weekend in Mumbai when I arrived including couchsurfing with an interesting guy, and also the one day spent seeing Hyderabad. I guess I didn't see much that made me want to come back, but I probably didn't get a very good sample. Hyderabad certainly had little to recommend it.

I guess in summary I can say that I would have learned and done much more maths at a 10 day conference on combinatorics, and seen much nicer parts of India on a 10 day holiday, so either would have been preferable.

Ubuntu 10.04 Lucid on X41 Tablet

2010-08-12T02:02:00.006+02:00

I just installed the latest Ubuntu on my X41 Tablet, and found that getting everything working was easier than what many guides for older distributions describe.

First I would recommend installing Cellwriter for entering text with the stylus and Xournal for note taking, drawing etc. Both programs work nicely, though are maybe not as advanced as their windows counterparts.

The stylus is supported out of the box because the xserver-xorg-input-wacom package is now installed by default. The only things that I found needed work were the special tablet keys: up, down, enter, escape, menu, reset and rotate screen.

I first used this post about 9.04 to get the first four keys working. Simply add the following lines to /etc/rc.local and they should work.

# PageDown, PageUp, Enter, Escape
setkeycodes 6e 109
setkeycodes 6d 104
setkeycodes 69 28
setkeycodes 6b 1

The other three are a little different. You also add something to /etc/rc.local, but this time the key codes we use are previously unassigned ones:

# Tablet Menu Key
setkeycodes 68 130
# Tablet Rotate
setkeycodes 6c 131
# Tablet Reset Key
setkeycodes 67 132

Once all this is added, it might be a good idea to log out and back in. (I can't remember if I had to do this for it to work.)

To make use of these keys I found I could simply use System - Preferences - Keyboard Shortcuts to assign them the commands I wanted. For example, to make the Menu Key launch Cellwriter I clicked 'Add' to make a shortcut called 'Tablet Menu', with command 'cellwriter'. Once created, you click on the new command ('Shortcut' column) to assign it, and press the Tablet Menu key. In my case it recognised the input as "SunProps", whatever that is.

The post mentioned above said this Keyboard Shortcuts method didn't work in 9.04, but it seems ok now.

The last problem is to make the screen rotate button work. This needs to rotate the display and the stylus input so that you can use it properly. For this I found this post helpful. However, I didn't need to follow all the steps. I only had to do the steps 5 to 7. That is,

$ sudo gedit /usr/local/bin/rotatetablet

Then copy in the script below (I've commented out some lines that seem not to be needed, see the comments on this post for more):

#!/bin/sh

# Find the line in "xrandr -q --verbose" output that contains current screen orientation and "strip" out current orientation.

rotation="$(xrandr -q --verbose | grep 'connected' | egrep -o '\) (normal|left|inverted|right) \(' | egrep -o '(normal|left|inverted|right)')"

# Using current screen orientation proceed to rotate screen and input tools.

case "$rotation" in
    normal)
#    -rotate to the right
    xrandr -o right
# xsetwacom set "Serial Wacom Tablet STYLUS" Rotate CW
    xsetwacom set "Serial Wacom Tablet" Rotate CW
# xsetwacom set "Serial Wacom Tablet eraser ERASER" Rotate CW
    ;;
    right)
#    -rotate to normal
    xrandr -o normal
# xsetwacom set "Serial Wacom Tablet STYLUS" Rotate NONE
    xsetwacom set "Serial Wacom Tablet" Rotate NONE
# xsetwacom set "Serial Wacom Tablet eraser ERASER" Rotate NONE
    ;;
esac

Also make it executable

$ sudo chmod +x /usr/local/bin/rotatetablet

Then use Keyboard Shortcuts again to make a shortcut 'Rotate' with command '/usr/local/bin/rotatetablet'. Again, the rotate key was recognised for me, and for some reason came back with the name 'Undo'. I guess these names are caused by the random choice of keycodes 130, 131 and 132. You can use any unassigned code you like. To find which codes are not in use look at

$ sudo dumpkeys

Lastly, if you wanted you could set up the little reset button to restart X or something like that.

Indian Trains, Foreign Credit Cards

2010-08-05T09:35:00.001+02:00

I'm off to the International Congress of Maths next week, and will be flying into Mumbai before taking a train to Hyderabad for the conference. After battling with the quirky Indian Rail booking website for some time I eventually got to paying for my ticket and found they don't accept foreign credit cards.

I fearlessly proceeded to google and found that there is quite a good site called Cleartrip that lets you book Indian trains (and also flights, hotels etc.) and they do accept my money. I can recommend the site for anyone else heading to the ICM thinking of getting some train tickets in advance.

As far as my trip goes, it's going to be a 17 hour overnight marathon covering about 900km. Because of this I took the easy way out, eschewing the authentic experience of 3rd class sleeper travel (costing about AUD13) and got myself a first clast airconditioned bunk for $50.

VMSSC 2010

2010-07-05T11:44:00.000+02:00

Last Friday was the inaugural Victorian Mathematics and Statistics Student Conference at our department here at the University of Melbourne. It was a single day conference for graduate students only with three streams of talks (pure, applied and stats) and some invited speakers. It all went very well, so thanks and congratulations are in order for the organisers.

I gave one of the short talks, and took the opportunity to talk for the first time on a problem I've been working on for a while. The question is to determine the chromatic number of graphs arising from collections of great circles in general position on the sphere. My slides are on my home page. This was the second talk I have given for which I made slides on my new (old) X41 Thinkpad tablet laptop, about which I'll say more one day when I get some time. It works quite well, and is a bit easier than making slides in LaTeX, especially when diagrams are involved.

Building Week

2010-06-07T04:20:00.000+02:00

I just finished a week of 'holiday' which I took to work full time on our new house. The project involves making a new bathroom, intalling kitchen cupboards, partly replastering the living room, new vinyl in kitchen etc. While I didn't get as much done as I had hoped (I never do), I am quite happy with the result. I worked about 10 hours a day for 9 days straight, so couldn't have done much more. Most of the work I did was plastering and carpentry. The main challenge remaining is to build the shower stall in the new bathroom. We may get someone in to help with the tiling. If things go to plan we should be well and truly finished by the end of the month, and ready for some new housemates. Unfortunately now that my holiday is over I return to my double life of builder/mathematician, and have to try to balance the two. One day I'll put up some photos of what we've done.

The worst day I can remember.

2010-05-17T07:47:00.006+02:00

Yesterday I had the worst day I can remember having. No single especially bad thing happened to me, but the endless chain of cock ups that made up the day almost defied belief. The previous two days I had spent working on our house. We had a plumber in to lay the pipes for a new bathroom, and I was working hard for about 12 hours each day. This meant I was ill prepared for my worst day ever. This is how it unfolded.

I got up at 7 with Nu to finish steaming the walls of our living room with a wall paper steamer. I planned to return the machine to Bunnings Hire at 9.30 and then go on to Caulfield to pick up a bathroom vanity we had bought on ebay.

Fail 1: I got to Bunnings and the hire shop people soon pointed out that I had forgotten the cap for the machine's water tank. Result: Lose 30 minutes driving home and back.

Fail 2: I got back to Bunnings with the cap only to be told that I had brought the wrong receipt with me and couldn't get the $100 deposit back. Nu had given me the one from last weekend when we hired the same machine. Result: Give up on Bunnings for the moment and go to get the vanity.

Fail 3: I arrive a the house in Caulfield and soon discover that despite my measurements, the vanity will not in fact fit in Nu's car. The problem is not the size of the boot so much as the size of the hole it has to go through to get into the boot. Result: Need to go to parent's house to get dad's station wagon.

I drove to mum's place and relaxed long enough to share an eggs breakfast with my family, then got my brother to accompany me to get the heavy vanity.

Fail 4: After getting the vanity in the correctly sized car we set out for Richmond. Due to poor navigation on both our parts we end up taking a far from optimal route along Kings Way and then east along Swan St. Result: Spend an extra half hour in a (football related?) Sunday traffic jam.

My brother and I return to mum's place with a shopping stop at Bunnings on the way, where I finally get the deposit back. We relax there and Nu decides to join us since the Richmond house is too cold. In theory this involves a 20 minute train ride...

Fail 5: According to the internet Nu needs to take a Lilydale bound train from Richmond to Camberwell, then change to the Alamein line to go to Burwood. There is a bus replacement service on the Lilydale line after Camberwell. I walk up to Burwood station at the appropriate time to meet her train. A few minutes before it is due she calls me to say she is in Camberwell and the replacement busses are so full she has missed 3 of them. I explain that the replacement busses will not in fact take her to Burwood, and she should try to catch the next train to Alamein. This will arrive 20 minutes later. The confusion makes us both very angry at each other and as a damage control measure I walk back home to get a car to pick Nu up from Burwood. Result: I waste 20 mins walking in the cold, Nu wastes 20 mins at Camberwell station.

On a normal day any one of these stuff ups would be reasonably tolerable, but my already fragile mental state (due to the hard work of the last week) was driven past breaking point. Forgiveness and serenity in the face of adversity are traits of great human beings. I am a mere mortal. At least now I can almost see the funny side of it.

New House

2010-04-28T02:18:00.001+02:00

Nu and I returned to our respective parent's houses when we came back from Germany, but always intended to move out again. Instead of renting Nu's dad suggested that he would buy an investment property and we could rent it from him, and we thought this sounded like a good idea. So after much searching they chose an old 4 bedroom townhouse in Richmond which we'll set up as a share house. It's a great location just 200m from the main station.

We finally moved into the house last weekend, but there is a lot of work to do to get it ready for other tenants. There wasn't really a proper kitchen so I bought this kitchen (including stove, dishwasher rangehood and sink) on ebay for $150.

We also need to install a second bathroom because currently there is just one small bathroom with a bath and sink, and an outside toilet. My dad and I will try to do most of the carpentry, and we'll get a plumber in to do the fittings.

Another large task is redecorating the living room since Nu decided the old wall paper had to go. Unfortunately under the wall paper we found all kinds of stuff that will need some work to repair.

The house has no heating at present so we'll get something installed, probably a reverse cycle airconditioner. We'll also try to make the house more draft proof, since being an old weatherboard cottage, there are quite a few gaps. Also the ceilings are very high (3.2m) which is pretty but doesn't help with heating.

Nu's new bike

2010-02-27T11:01:00.003+01:00

Nu just got a bike as part of her plan to learn to ride so she can ride part of her trip to Uni. It's a lovely Austrian mixte from the early 80's. It's made by Puch / Austro Daimler and has components from all over Europe. I think it was a reasonably high spec model for it's time, though not particularly collectable now. Nevertheless, it's in beautiful original condition and rides really nicely. It's a very big frame, but Nu is a tall girl and she's quite happy riding it. All I've done so far is clean it a little and replace the tyres with Schwalbe Marathons with reflective side walls (which you can see shining in this flash photo).

It's Official

2010-02-15T05:17:00.000+01:00

Today I have finally officially begun my PhD at Melbourne Uni. I've been working here unofficially since about September, but now I am fully enrolled, and may even be paid soon. Hooray. I originally planned to start early January, but the enrolment process took a bit longer than it should have. I'm quite optimistic about studying here, and I should get more into it once I meet more of the other students and go to some of the academic and social events. One of the good things about the department is that there is a large cohort of grad students, so it should be fun.

In other news, Nu and I are working on finding a new place to live. We are both with our parents at the moment, which is a big change after being away for 3 years, so we'll be glad to have our own space again. Current thinking is that we'll move somewhere like Richmond or South Yarra to be both close to the city and near the train line that goes to Monash, where Nu will be doing her Honours this year.

33ACCMCC in Newcastle

2009-12-14T11:42:00.036+01:00

After arriving in Melbourne on Saturday 5th, I flew directly to Newcastly the next day for the 33rd Australasian Conference on Combinatorial Mathematics and Combinatorial Computing from December 7 - 11. This was the first conference I had travelled to, and only the second conference I have attended. I stupidly squandered the opportunity to get a funded trip to a conference while in BMS Phase I because I was so busy with courses. The conference was resonably interesting, though I began to see that not many Australian combinatorialists were doing the kind of discrete geometry (e.g. polytopes) that I'm interested in. Most talks were on things like design theory, latin squares, finite graphs and the like. I gave my talk on graphs with ambiguous chromatic number and the slides are on my new home page at unimelb.

More exciting than the conference was the great time I had couchsurfing with some of the locals. I ended up helping a little at a soup kitchen, seeing my host's brother's school jazz band, chatting about motorsport and so on. It was much more enjoyable and relaxing than staying in the hostel where I had to stop for the first couple of nights, though the Newcastle YHA was very nice.

Sri Lanka

2009-11-13T04:13:00.001+01:00

It's been a while between posts recently, and it will remain so because this month I'm in Sri Lanka. Nu and I arrived on the 9th in Colombo and will be traveling around by ourselves until the 20th when her family will arrive. The main purpose of the trip is to attend her cousin's wedding at the end of the month. For now we are exploring the ancient cities of the central and northern regions, basing ourselves in Anuradhapura for five nights. It's been fun so far. We are traveling with a hired car and driver, and Nu's basic knowledge of Sinhalese makes it a lot easier. Needless to say there are many interesting and different aspects to the country, not least the chaotic experience of road travel, but I'll have to wait til later to elaborate on them.

Review: Schwinn Madison vs. Fuji Track (2009)

2009-10-20T04:26:00.003+02:00

Since I now own a Madison, and owned a Track for a few months earlier this year, I thought I'd write up a review of these two bikes. They are both at the budget end of the fixed gear bicycle market, with steel frames and basic components. It is clear that these bikes are not really intended as serious track bikes, though I have heard that the Fuji is used as a rental bike at some velodromes. To me the Madison seems aimed more at the commuter market.

I got my Fuji for $420 (AUD) at Goldcross while they had a sale on road bikes. The RRP is $600. The fuji came without brakes and with a fixed gear only on its fixed-free hub, and the high gear ratio of 48/15 did seem to lend itself more to the velodrome. I found many of the components on the Fuji rather cheap and nasty. The seat was quite ugly, and the extremely basic Formula hubs without sealed bearings ran quite rough. I didn't like the track drop handlebars because of their deep drop and strange curve in the top part that meant there were no comfortable hand positions on top. I guess they were meant to be basic track drops, so this is understandable. They were at least nice and light. I swapped them for a second hand Syntace Stratos triathlon bullhorn which I found very nice. The cranks were very basic and I found I had to swap the front chainring to the inside of the spindle to get a straight chainline. The Fuji had holes for both front and rear brakes, but I added just a front brake with a triathlon style reverse lever. You can see photos in this previous post. Despite the poor quality I had a lot of fun riding this bike around Berlin, though in a city with more hills I would have needed a lower gear. The frame geometry was forgiving for a beginner, and had no toe-overlap with the front wheel. Of course, the quality of the components would have become more important as the bike got older and things began to wear. Nevertheless, I felt it was a good frame on which to build up a nice bike by replacing things as they needed it. I only sold the Track because I was leaving Berlin and couldn't take it with me.

After enjoying my first fixed gear bike I was happy to spend a little more on the second one. I got my Madison for $720 at BikePro, also on special from the RRP of $850. I was quickly aware that the Madison was a significant step up in quality over the Fuji Track. The frame seems a little chunkier, with a nicer 'aero' fork. The components are a lot better, including an okay San Marco seat, smooth cartridge bearing Formula hubs and FSA cranks. Importantly, for the extra money you got front and rear Tektro brakes, and both a fixed cog and a freewheel. The ratio on both sides is 48/18 which is quite good in Melbourne, especially for my fairly flat commute along the Yarra and Gardiner's creek trails. The presence of brakes, and also of holes in the fork ends to accept mud guards, are what make me say that this is a commuter bike. Also, it doesn't seem aimed at the fashion victim hipster set (like e.g. SE Lager) because it doesn't have any 'cool' stuff like a top bar pad. The black model which I have is reasonably subdued, though the previous bright yellow colour was very eye catching. As mentioned, the frame is chunkier than the Fuji, particularly the bottom tube, so it doesn't have the skinny retro look, though it is thinner than a typical aluminium frame. On both bikes the joints are welded in the modern way with internal butting. Both have holes to accept drink bottle holders, and neither have braze-ons for brake lines (the rear line on the Madison is taped on). The rims on the Madison are also better with a deeper V and colour matching the frame. Finally the standard drop handlebars are much more comfortable, and I have not yet tried my Syntace bullhorn on the bike. This is mainly because of the 31.8mm clamp size as opposed to the 26mm on the Fuji. On the road I would say the Madison is a little harsher and more responsive. It does have toe-overlap with the front wheel, but it is only slight and has never caused me a problem. The weight of both bikes is similar, around 10kg (22lb), with the Madison perhaps a little heavier. Photos to follow eventually.

Mohammed Abouzaid - Clay Mahler Lecture

2009-10-07T07:13:00.008+02:00

This is a very late post about a talk I saw a long time ago as part of the Clay Mahler series of lectures. The series included talks by Terry Tao in various Australian cities, though sadly I missed them all. The one I did catch was a fascinating talk called Understanding hypersurfaces through tropical geometry by Mohammed Abouzaid from MIT. Sadly I can't find the slides of this talk online, but I'll just say that while it went mostly over my head, the vague idea was that the topology of some algebraic varieties could be encoded as tropical varieties. The way it was explained, it seemed like this was a somewhat surprising application of tropical geometry, and it made me want to try harder to find time to study tropical geometry.

The Big Move (II)

2009-09-20T06:27:00.003+02:00

I'm now more or less settled in back at home in Melbourne, so it's time to write a bit about the journey here. During my last month in Berlin I tried to cram in some of the things I'd been neglecting to do for the last two years. My last weekend was no exception. On the Friday night before I left I went out to celebrate a friends birthday, and ended up heading to a club with Kaie in an attempt to sample a famous Berlin club before leaving. We chose SO36, and it was fun, but the crowd was so young it made us feel a little out of place. After getting home in the early morning I had to get up after only a few hours because Saturday was my last chance to go to shops before leaving early Monday.

I got a good sleep Saturday night, but Sunday night turned out equally sleepless. On Sunday afternoon I met up with Moritz and Kaie for the last time and we took a walk from the TU to Schlosspark Charlottenburg. This was a typical example of how Berlin keeps surprising me even after 2 years. I had never bothered to check out this park which was maybe a 15 minute ride from my house, but it has a large and very nice formal garden, and a lot of general park area as well. Had I known what it was like I'd have come more often. After the park we went to Savignyplatz for some dinner and then said goodbye. I got home at a reasonable hour, but I still had a fair bit of cleaning to do and only finished at about 2am. The problem was I had to get up at 7.

So with less than adequate sleep on two of the last three nights, the hard bit began. First task was to get to Hamburg on the train, then hope that Emirates accepted all my luggage. They had recently increased their luggage limit to 30kg, but I was going to push it. I had about 32kg in two checked bags, but my cabin bag (which they didn't weigh) was 12kg instead of 7, and I had a camera bag too. To top it off I was trying to convince them to let me take my light but oversized guitar in the cabin too. Luckily they accepted it all, and my guitar was spared the ravages of the baggage handlers. It seems that it's really up to the cabin crew as to whether they accept oversize items in the cabin, so you don't know until you get through the door of the plane. Luckily it was accepted on every leg as I flew Hamburg - Dubai - Singapore with Emirates, and then Singapore - Melbourne with Qantas. Door to door time was about 33 hours.

Yet another bike

2009-09-17T04:19:00.001+02:00

Shortly after getting home I bought yet another bike, a Schwinn Madison fixed gear/single speed to replace my Fuji Track which I sold in Berlin. I'm really happy with the Madison. It was a bit more expensive than the Fuji, but has much better components (especially the hubs) and came with brakes and both a fixed gear and freewheel. The gear ratio (on both sides) is 48/18 which feels much lower than the 48/15 I had on the Fuji. Melbourne has much more hills than Berlin so this is a welcome feature. I have ridden in to the city centre from my house, which is mostly along the Yarra river, so pretty flat, and also to Nu's house which is quite a hilly ride. For the hilly ride the freewheel is best because it lets me roll down the hills without feeling silly pedalling really fast. The fixed gear was fine for the city ride, and I even felt that once I build up a bit more fitness I could raise the gear slightly and go a bit faster, maybe with a 17 or 16 tooth cog.

Made it

2009-09-02T13:23:00.002+02:00

I made it home to Melbourne. Another massive trip, this time with a train to Hamburg then flights to Dubai, Singapore then Melbourne. About 40 hours door to door, though I did manage to sleep a bit. Tired now, more later.

Photography

2009-08-29T12:31:00.000+02:00

For a while I have been marginally interested in photography. I enjoyed photography classes in school, and remember taking photos on my dad's manual film camera back in '98 when my family went on a 3 month tour of Australia. After that I had a modern Canon SLR film camera which was unfortunately stolen around 2002. I didn't do much after that until I got a Canon digital SLR last year, and this has rekindled my interest.

As part of trying to see exhibitions and museums in Berlin before I leave, I went to the Helmut Newton gallery a few weeks ago. I liked Newton's work quite a lot. Here is an interview with him that I found quite interesting.

Now as is normal when I get interested in something like this, I quickly got distracted thinking about all the gadgets that I could acquire instead of just taking some photos. (I have taken a fair few photos recently and will eventually put up some samples on picasa). In general I'm quite into DIY and doing things on the cheap, and there are various possibilities for this in the realm of photography. One obvious thing was to try to use my dad's Minolta lenses on the digital camera. Some of them are quite nice (e.g. a 50mm f1.4), but unfortunately these lenses are not as easy to fit to a Canon camera as some other old lenses. This is because of the 'flange focal distance' of the different lens systems. This is the distance from the back of the lens to the sensor/film plane, so the 'depth' of the camera body more or less. The Canon system has 44mm and the Minolta MD has 43.5mm. This means the lens would have to sit 0.5mm inside the body to be able to work normally. If you have it further out it will no longer be able to focus on infinity. Actually someone has overcome this problem with a replacement flange for Canon bodies, but this would require a body just for Minolta lenses.

Another project I've been thinking of is building a 'perspective control lens'. Such a setup allows you to shift and/or tilt the lens with respect to the camera body. Shifting changes the perspective, and tilting creates strange focus effects as the plane of objects in focus is no longer parallel to the sensor. These lenses are very expensive if bought from Canon, or not very good (according to reviews) if you buy a cheapish alternative such as this.

So the obvious question is can you build one yourself? After all, it just needs a mechanism to tilt and shift the lens. Many people have tried this (e.g. here) normally with some sort of rubber tube from a toilet plunger or something and a cheap lens on the front, and the results are good. It's best to use a lens from a medium format camera because it makes a larger image, and has a large FFD so there is space for the shifting mechanism. I found the wiki page on lens mounts very useful for finding the FFD of different systems. It seems to me that a good choice for a lens to use might be Kowa or Bronica. Many of the other brands with large FFD (say 80mm or more) seem to be more expensive on ebay. Anyway, I'm wondering if it might be possible to make a homemade 'shift box' out of wood, perhaps even with tilt as well. I haven't seen any such project, but this could give a sturdier result than the rubber boot methods. Maybe you could use a cheap macro tube on the camera side, then a box with some sort of sliding lid to which the lens is attached.

Leaving Berlin

2009-08-27T22:13:00.002+02:00

My last few weeks in Berlin have been really nice, though quite busy with packing and organising things. It's still not over, but most things are under control now and I should be ready for my flight on Monday without too much trouble. I've had a few visitors recently and have taken the opportunity to cram in a few more touristy things around town which has been fun. After a day or two of showing people around I am quickly reminded why I prefer living in one place for an extended period rather than touring.

There will be many things to do when I get back like seeing Nu and my friends and family, and making arrangements for enrolment at University of Melbourne. Also a new bike might be on the cards since I hope to ride a lot more, and I'd like to find a cool old ladies bike to fix up for Nu. I've also been getting more into photography recently and hope to find time to put up a few albums on picasa. Then there's music, hopefully finding time to play my flamenco guitar that I got while I was here, and the other guitars at home. But number one priority will be to get quickly into a routine of maths study. I want to get off to a good start because the change of Universities will bring inevitable delays, and I'm not getting any younger. I still hope to finish before I'm 30, and I think my new scholarship will be for 3 years beginning around my 27th birthday, so it'll be tight.

Accidental Art

2009-08-13T16:51:00.007+02:00

We just got a new computer in our office and it behaves slightly strangely when I login to Open Suse. After entering my password some random junk flashes briefly onto the screen before the desktop appears. It seems to be a mash up of graphics from the last session, perhaps from the video card's memory cache or something. Anyway, I managed to capture some of these weird creations with the printscreen button just before they disappeared. These collages appeared after I was looking at facebook, and have only been cropped to show the more interesting parts.

Stuff for sale

2009-08-10T11:59:00.002+02:00

I have a number of things that I need to get rid of before I leave at the end of the month. If you're in Berlin check out the picasa web album below. At the moment there is my TV, TV trolley and dining table, but more will be added.

For Sale

Chinese censorship III

2009-08-07T20:01:00.004+02:00

Today was the big day of the screening of '10 conditions of love' at the MIFF. There have been further attempts by Chinese officials to impose their censorship regime in Australia. This article describes how the Chinese consul-general of Melbourne met with the Lord Mayor of Melbourne to demand that he force the film's withdrawal. The thing they don't seem to get is that, as far as I know, the Lord Mayor should not have the power to dictate which films the MIFF can show.

Here is another article I found giving a Taiwanese perspective to the story. The editors of this newspaper are at pains to highlight that Taiwan (unsurprisingly) does not support the attempts at censorship, despite the fact that one of the films withdrawn in protest was Taiwanese. Apparently it was the Hong Kong based distributors who submitted to the pressure to withdraw it.

In the end there were no serious incidents at the screening, but it still remains to be seen what will happen with Australia-China relations now the film has been shown, particularly with the City of Melbourne and its sister city relationship with Tianjin which was rumoured to be under threat.

Lashi's eclipse photos

2009-07-27T00:37:00.003+02:00

My good friend Lashi just got back from photographing the recent solar eclipse in China. Check out his images, and also his shots of the eclipse in 2006 from Egypt where there wasn't so much cloud. Great work!

10 things not to do...

2009-07-26T22:16:00.005+02:00

Today I saw a German sketch comedy show on Sat1 called Kesslers Knigge. Now, I know that humour is probably the hardest aspect of a foreign language to understand, but a lot of this show was just visual, and I could follow it quite easily. I didn't find it that funny, though I did laugh at a few things. I think sketch comedy is pretty hard to get right, and while there are a few good British shows, I've seen plenty of poor efforts in Australia, and also from Britain.

A few things grabbed my attention about this show. The first was the rather German format of the show, divided into topics entitled "10 things not to do when ... " with the 10 funny things duly numbered on screen. It made me imagine a standup comedian saying "I will now tell ten jokes about Pools. Here is the first joke: ... Laugh now. ... Ok, enough laughing. Here is the second joke: ... ". Seriously though, such a rigid format reduced the potential for surprise and variations in the timing of the jokes. Some of the things were funny enough, but I'm not sure the demand of finding precisely 10 things for each situation did much for the standard of the jokes. The second thing I noted was in the section about having a barbecue with your friends. One of the 10 things not to do was to announce "Hey everybody, today we're having a vegetarian barbecue!" Preposterous!! I mean, this is clearly as ridiculous/stupid as the other examples such as falling asleep and grilling your own face, or standing over the grill with a fire hose in case of emergency, or cooking human flesh. (Actually as I've said before, despite loving their meat, Germans are very accomodating to us vegetarians.)

Chinese send haxorz, take footy home

2009-07-26T11:29:00.003+02:00

Following my previous post about Chinese attempts to project their censorship regime internationally, comes news that they have escalated their efforts to stop the film 10 Conditions of Love about an Uighur dissident being shown at the Melbourne International Film Festival.

After Fail 1: Ring organisers and demand film be retracted comes Fail 2: Send in haxor legions and Fail 3: Withdraw other Chinese films in a huff. Of course none of these tactics will force the organisers of a film festival in a free and democratic country to withdraw a film whose political content the Chinese government dislikes. In fact they will obviously just strengthen their resolve to show it, and also create heaps of free publicity for the film.

To summarise, Fail 2 involved vandalising the MIFF website, which currently seems unreachable either due to increased traffic or perhaps more attacks. It seems you can still see some of the hacks in the google cache. Fail 3 involved coercing the directors of the other Chinese films programmed to withdraw their films. This has the unfortunate effect of disrupting some funding from the Hong Kong Economic and Trade Office. On the other hand, these actions have resulted in extra screenings of certain popular films, including, you guessed it, 10 Conditions of Love. What's more, the disruption to the website will probably have little effect on festival attendance since the programme is widely published in paper form, and filmgoers can still resort to ancient 'cash' technology in order to purchase tickets at the box offices.

Fixie ist weg

2009-07-23T22:21:00.003+02:00

My preparations for leaving have advanced quite a lot recently. Just a few minutes ago I sold my Fuji Track bike to a happy customer, and this morning I met with my landlord and some new tenants that I found, and they drew up a contract. There is still lots more to do, but things are progressing nicely. I will miss riding the fixie though. I'll just have to wait til I get home and buy another one.

Gratuitous car photos

2009-07-16T21:05:00.005+02:00

We haven't had a photo of my brother's and my MX-5 recently, and I have some nice ones from when I visited it in April. Note the nice rims my brother bought for it. It'll be nice to drive it again when I get home, though of course I will be cycling whenever possible. It's really hard being an eco-petrol-head...

How not to censor people in Australia

2009-07-14T23:23:00.004+02:00

I just read this article in The Age about Chinese consular officials demanding the withdrawal of a film from the upcoming Melbourne International Film Festival. Such simplistic tactics might work in China, but telling a bunch of artsy types that they can't show some film, when they are clearly completely in their power to do so, is not a good way to stop the film being noticed in Australia. It will (hopefully) have the very opposite effect. If you're able, may I suggest you try to see the documentary mentioned just to prove me right! With huge resources contracts, the Chinese government may be able to make the Australian government and big businesses abandon any moral principles they might have had, but I'm pretty sure they won't be able to manipulate some good hearted film nerds.

As a side note, you may have heard of the buzz in Australia about some Rio Tinto executives being arrested for spying while in China to negotiate a deal between Rio and the Chinese government. Of course, it's possible that the accusations are true, but when you consider that people arrested for spying in China can be held for long periods without access to lawyers and be coerced into confessions, you start to understand the problem with dealing with totalitarian states used to exercising arbitrary power over their subjects. Maybe, just maybe, it would be a good idea to refrain from dealing with people with whom you have fundamental ethical disagreements. At least this is my instant reaction when I hear this stuff - if you don't want your employee's human rights abused, maybe don't deal with China. Of course this is 'economically out of the question' when there are mining contracts at stake. Turning a blind eye makes Rio, and all of us, complicit in the abuses that occur. This is a fundamental moral truth. If you can't conform to your own ethical standards, you can't really claim they are your standards.

Grand Sale, Grand Sale!

2009-07-09T17:47:00.006+02:00

I should really start advertising things that I want to sell before I go at the end of August, so if you're in Berlin check out these things and let me know if you're interested:

Fuji Track '09 fixed gear bicycle. 350euro or best offer [SOLD].
68cm Grundig TV, with nice rolling stand. 60euro, separable.
Samson Media One 4a home studio monitor speakers. Awesome for iPod etc - tests are welcome! See this post. Price is fixed at 100euro since otherwise I will take them with me. They're in perfect condition, new price 150euro.
Furniture including: Dinner table extends to seat 10, with 8 chairs. Metal double bed with lattice and mattress. Two large rugs. Ask me for details and prices.

Eventually I'll put up more details and photos of stuff I have for sale.

There is also my apartment for rent: 2 bedroom, 62 m^2, einbauküche, in Turmstraße, Moabit. 440euro warm per month. Kaution (bond) is 3 months kaltmiete, 1020euro. Provisionfrei (no one off fee) of course. I'd like to find a 'nachmieter' to take the apartment in it's condition as it is (nice and clean, but paint is not perfect). Could throw in some furniture to sweeten the deal.

[Edit: The deal seems to have been quite sweet, as the flat is gone. In fact the winning bidder rang me literally 1 minute after I posted the ad on wg-gesucht.de!]

Laksa recipe - Part II

2009-07-07T22:00:00.002+02:00

Part I described the preparation of the Laksa paste. Once that's made, making the Laksa is relatively quick and easy. My recipe is vegetarian, but if you want to add chicken or seafood it's probably not hard. Make sure it's cooked before adding it to the soup though! This recipe is for about 4 serves.

Ingredients:

1/2 cup of Laksa Paste
1 onion
Some mushrooms
1 capsicum
2 small carrots
Broccoli
Bean shoots
Fried tofu puffs
Noodles of your choice
Veg stock powder
400ml can coconut cream
1L water

Method:
The best bet is to cook things separately when necessary so as to make sure everything gets cooked the right amount, then assemble it all at the end. When using a chunky paste like we made in Part I, the trick is to mix the paste with the coconut milk and then blend it thoroughly. The vegetables here are just suggestions, you can use what you like. Cut them into strips and start with the ones that take longest. Fore example, I like to cook the carrots and broccoli in a fry pan with a little bit of water and a lid on high heat, to sort of steam them. Stir them occasionally to check they don't stick. When they are a bit softened add the onions then mushrooms then capsicum and fry them. Add a bit of the paste/coconut mix to get them to pick up some flavour. The coconut cream has lots of fat that helps them fry too. At the end throw in the bean shoots to just warm them - they don't need to cook. While this is happening cook your noodles and strain them. Also heat the rest of the coconut/paste mix in a large pot and then add boiling water from the kettle. Add the tofu puffs, cut into halves or quaters, so they can absorb the soup. Check the taste of the soup and add veg stock if it needs more salt, or more water if it's too rich. Now you have everything needed to assemble the Laksas in some large bowls. Put the noodles in first then vegies and then top up with soup and tofu puffs.

It takes some experimenting to get all the quantities right. For this reason it's best to assemble it all at the end rather than mixing in a huge pot. Don't feel obliged to use all the vegies and noodles you prepared, they can always be used in something else. If you're keen, take notes on what you did like I do, and then you can adjust things next time. Soon you'll have the perfect Laksa.

Old News

2009-07-07T21:00:00.003+02:00

Many of you who know me are already aware that I recently made a big decision about my future, but for those who don't know here's the news. I'm heading back to Melbourne next semester to continue my studies. The reason for this change of plan is that I want to be with my girlfriend, and we realised that if I stayed in Berlin for the next 2 or 3 years our relationship was doomed. Of course, it will be very nice to see my family and old friends more often too. So I'm transferring to University of Melbourne, and will be studying with David Wood who last year began a 5 year ARC QEII Fellowship. I will be sad to leave Berlin, but I hope to come back regularly, and maintain contact and collaboration with my colleagues here. I am also sorry to leave the BMS after all they did for me, but as some of my close friends reminded me while I was making this decision, there are more things to life than maths.

This means I will be moving out of my flat (2 bedroom in Moabit) at the end of August and selling/giving away lots of stuff including furniture and my new fixed gear bike, so stay tuned for info on those, or contact me if you're super keen.

Obesity Epidemic

2009-07-04T13:38:00.004+02:00

We've all heard of the (somewhat ridiculous) 'obesity epidemic' affecting some western nations, not least Australia, but right now I'd like to talk about a different obesity epidemic affecting the worlds car designers. I just read a few reviews about the interesting new BMW 135i coupe. Car design has long taken for granted a constant 'bracket creep' in which new models constantly grow relative to their similarly named predecessors, and new model names are introduced at the small end. Why this is necessary I'm not sure.

Anyway, considering the 1-series coupe, I harboured faint hopes that this might be a car of comparable dimensions to the classic 3-series of times passed, the extremely successful 1980s E30 for instance. I was disappointed to learn that the massively powerful 135i is also massively massive, weighing in at a lardy 1,560kg. That's right. One and a half tonnes for a 'compact sports sedan'. The 325i of 1986, a larger car by model designation (though there was no 1-series at this time) weighed just 1,200kg. The supposedly little 'Porsche killer' 135i is in fact 100kg heavier than a brand new 911 Carrera.

This is an example of an advanced manufacturer making a supposedly small car. It makes you shudder to think of the excesses of low-tech American cars which aren't even trying to be small. If we are serious about making fuel efficient cars, this problem of mass has to be addressed just as much as making more efficient engines. There's no point making a better engine just to put it in a lardier car. People will argue the increased mass is due to more advanced safety equipment, but this is only partially true. There is also a large amount of less worthwile junk added to new cars along with safety equipment. Besides, new materials such as advanced composites should be able to offset the weight of added features.

I guess in the end we may just be seeing 'market forces' playing out. With continual advances in engine technology, consumers opted not for reduced fuel consumption, but for bigger cars with more junk on board. Until they are made to pay for emissions they won't be inclined to reduce them.

New paper, sort of

2009-07-03T17:54:00.005+02:00

I have just finished updating a paper that I started as part of my Bachelor's thesis and initially put on the arXiv about 2 years ago. You can see the new version here. In the paper I construct some unit distance graphs that can be coloured with a certain number of colours if you have the Axiom of Choice, but need more colours if you use Lebesgue measurable sets instead. My old version had rather basic proofs, and I have managed to improve the bounds on measurable chromatic number and generalise the construction to n dimensions. The old version was rejected by a journal (after a year of refereeing!) but hopefully this version has more success, this time with JCTA where I just submitted it. After a few weeks working just on this short paper I'm looking forward to doing something else!

A New Kind of Proof

2009-06-26T17:24:00.006+02:00

For over 50 years mathematicians have puzzled over the famous Chromatic Number of the Plane problem:

What is the least number of colours required to colour the Euclidean plane so that no two points distance 1 apart receive the same colour?

For about the same time it has been known that the answer is somewhere between 4 and 7 inclusive. Now with the help of the amazing new 'computational knowledge engine' Wolfram|Alpha, the question is finally settled. It's 6! (see screenshot above) The result was proven with a new proof technique being developed by Stephen Wolfram and a team of randomly chosen first year science students: Proof by Appeal to the Internet. Wolfram realised that with this new technique he could quickly settle long standing problems by simply choosing an answer and programming it into his universal knowledge dispenser.

[Edit (4/8/09): Alpha's response to "chromatic number of the plane" has been changed. It now responds with 4, claiming that it interprets the input as "plane, (map) chromatic number", which could generously be taken as referring to the four colour theorem. It is still an entirely useless response.]

Reverse Cold War

2009-06-24T22:26:00.000+02:00

I have just been reading Senator Christine Milne's address to the National Press Club about Australian climate policy. I also recently finished reading The Berlin Wall by Frederick Taylor and was struck by some interesting parallels and differences between the Cold War nuclear standoff and the current international negotiations on climate change action.

Both scenarios invoked a fear of catastrophic destruction in the future. I am too young to remember the cold war, indeed it was almost over when I was born, but it must have been very unpleasant for citizens of the East and West to live at the mercy of the actions of their ruling elites. While no-one, not even the military leaders, wanted a nuclear holocaust, they nonetheless played a game where one false move by either party could have initiated such an outcome. The aim of the game seems to have been to go as close to the edge as possible, so as to best intimidate the other side, while not actually going over the edge.

Our current global game of flaunting disaster is very different. Most sensible people now believe that our activities have the potential to drastically change the planet for the worse during this century. While we are not threatened with such an immediate catastrophe as total nuclear war, the results of climate change within our lifetimes could be similar in gravity. This lack of immediacy seems to add to our bravado, but the game being played has rather different rules to the nuclear standoff.

Firstly, what is the aim of the climate negotiators? Well, being modern rational leaders driven mainly by economic considerations, their aim is to optimise the economic outcome for their country. For electoral reasons they might even be mainly concerned with short term optimisation, but let's leave this to one side. It seems fair to say that even the most enlightened leaders are concerned primarily with the well-being of their citizens, which they measure mainly in economic terms.

What are the rules of play? Instead of one false move triggering disaster, it seems that now universal agreement is required to avert disaster. The attitude of most negotiating parties appears to be that 'I'm not playing unless everyone does'. This means that inaction from just one party has the potential to cause everyone to give up and accept disaster. In this sense I see it as a reverse cold war. Everyone has to take the leap into the unknown if we are to avert a crisis.

There are more important differences. Whereas in the Cold War fear of the unknown and the human tendency to preserve the status quo was on the side of peace, it is now working directly against us. On the other hand, in our current game the citizens themselves have the potential to play a much more decisive role. We are not simply at the mercy of our rulers, with only our vote to protect us. Individually we can make a difference whether our governments act responsibly or not. Sadly experience suggests that this is unlikely to occur on a large scale unless our leaders actually lead instead of following. But don't fool yourself - this in no way diminishes your responsibility as an individual.

Death

2009-06-19T13:03:00.001+02:00

Is death the strongest taboo in our society? After all, despite being a completely natural thing we seem to be rather intolerant of some jokes that are made about it. Take for example this highly controversial sketch by The Chaser:

This sketch which makes light of the work of charities that grant 'wishes' to terminally ill children caused so much fury that the show was canceled for two weeks. I find this a somewhat surprising case of self-censorship by the ABC. It is not the first time they have made jokes relating to the wishes of the sick - see this sketch. The Chaser have also made many jokes about charities, like this one about collecting money for a private school's rowing shed. These sketches tend to be aimed at pointing out the idiosyncrasies of our moral views on what is and isn't worth donating money to.

I would say that there is a perfectly legitimate criticism to be made of charities like the Make a Wish Foundation. They spend large amounts of money on entertaining terminally ill children when that same money spent elsewhere could feed many who are merely hungry, or prevent curable diseases, or provide them with education opportunities they wouldn't otherwise have. Such opinions are taken by some as a heartless attack on the poor dying children, but I don't agree.

The idea that it is worthwhile giving money to such children's charities reveals much about our moral beliefs and attitudes to death. Briefly, here are a few points:

It reinforces the idea that death, even in young people, is unnatural and should be compensated for. Like adults, children will always be susceptible to disease and encouraging the view that it is unnatural will probably not help the victims or their families to accept it. Acceptance is a key step they must take to reach peace.
It reinforces the idea that a life is made worthwhile by fleeting pleasures such as trips to Disneyland or whatever. This hedonism is a key cause of discontentment in our society.
It is a classic case of the effect of proximity on our moral decisions. Why are those near us more worthy? Assuming you don't know the child personally, why should they take precedence over those in far away places who need much less.
Is it clear that creating a huge excitement for the child is a good idea? After such highs there could well be deeper than usual lows.

In no way do I wish to say that an ill child should just be given up as a lost cause - I am only questioning the benefit of donating money towards extravagant gifts. If someone is truly concerned for such children they should consider sharing something more than money with them. Offering companionship and compassion in a simple way could be just as helpful, if not more.

Returning to the theme of death, this reminds me of another kind of charity one could question. How does one justify giving money towards expensive research into diseases such as cancer which affect mainly the elderly in affluent countries? This seems to me another case of us rallying against the inevitability of death. I would say that it is more important to support efforts to end violence, hunger and oppression that stop healthy people from living in peace.

As a final note, I would agree that the Chaser's sketch wasn't one of their funniest, but here is another sketch by The Onion which does the job much better. However, it doesn't really have the same critical value.

Exorcising Demons

2009-06-18T18:57:00.004+02:00

I finally took the plunge into the cleansing pool of pure Linux on my laptop (IBM Thinkpad T40). For a few years I had run Window$ XP alongside Ubuntu (6.06), but I knew one day I would go all the way. In fact I went all the way, in that I totally deleted even the hidden recovery partition that would have allowed me to restore Window$. So here are a few tips related to some problems I had while upgrading.

Issue 1: GRUB Error 18

I decided to wipe out the IBM Pre-desktop Area, which was a small partition at the end of my disk. My new installation of Ubuntu 9.04 was into a partition which included some of this area. It turned out that this caused me to get GRUB Error 18 on booting, and the GRUB menu would not load. I used the default installation setup of installing GRUB partly on the MBR with the rest of it in the new Linux partition. I kept my old Ubuntu installation in a separate partition.

The meaning of GRUB error 18 is Selected cylinder exceeds maximum supported by BIOS. This means that GRUB is trying to boot an OS which is outside of the area on the harddisk that the BIOS would allow. This commonly occurs when you use a large disk with an old BIOS that hasn't heard of such big disks. I was initially doubtful since I am using the original hdd, but this was precisely the problem. The reason is that the BIOS was set to exclude the area reserved for the IBM Predesktop Recovery Thingo, so would not allow GRUB to read my partition that overlapped this. (My partitioning tools had no problem seeing the whole disk and writing to the protected area). The simple solution was to go into the BIOS setup and disable the protection of the Predesktop Area. This option is found under 'security' in the main menu of the BIOS editor. After this all was well and both Linuxes booted without problems.

Issue 2: Volume Keys

The second problem is a known bug with the sound volume hotkeys on Thinkpads that affects Ubuntu Jaunty. Basically the volume keys worked but there was no on-screen or software recognition of their being used as in previous releases. The workaround for this bug is documented here. The trick is to download an old version of the hotkey-setup package. You can uninstall the standard one with Synaptic Package Manager, then install the old one with GDebi. Once you have done this remember to go into Synaptic and lock the version of the package (from the Package menu). Otherwise it will be changed back next time you upgrade.

Verboten!

2009-06-14T16:57:00.010+02:00

Germans are generally quite reserved people in public, but there is one situation when they don't seem to hesitate to talk to complete strangers - when someone doesn't follow The Rules. I have witnessed this a number of times. Once I was in my local self-serve bakery and had taken a loaf of bread with my hands. To save paper I had avoided taking a tray and paper cover that people normally use, and just walked to the counter with the bread in my hand. Some guy behind me apparently took issue with this and started to lecture me on how you were supposed to use tongs and trays (even though the tongs couldn't hold a large loaf). So unexpected was his attempt to talk to me that I didn't even realise until later that he was talking to me and not someone else.

The second time I saw such a situation was at the Siegessäule when I was stopped at the lights with several other cyclists. One of them just started lecturing another about how he shouldn't ride with his earphones in because he had failed to hear him ring his bell. This may be sensible advice, but the complete lack of tact with which he began the conversation was quite amazing to me. The lecture went on even after the offender re-inserted his earphones and completely ignored the lecturer. I don't mind the idea of someone making a reasonable point to another, but they could at least initiate the conversation with some sort of greeting. I think in Australian culture, even if we want to agressively criticise someone, we begin with 'hey mate' (though this doesn't imply cordiality) and then use some level of euphemism to temper our criticism. We might say "Hey mate, I rang my bell back there but you didn't hear it, maybe you should turn your iPod down a bit." Not simply "Hallo. You should not..."

A third such situation occured to me today. I was out riding my new fixed gear bike which I have made almost properly legal. As far as I know it only needs lights to be 100% erlaubt and many people ride bikes without lights here, especially in the middle of the day as I was. Nonetheless, while I was stopped looking in a shop window some middle aged guy did not hesitate to stop his bike, look mine up and down, and then begin lecturing me on how 'es ist verboten... this and that'. I was completely calm because, like the other cases, he didn't seem particularly angry or agressive, he just felt the need to tell me the rules I was breaking. I didn't get to test my theory about the curt openings because I ended up opening the conversation myself with 'hallo' since he obviously had something to say. Initially I thought he might actually be interested in my cool and unusual bike, but I rather suspect it's unusual appearance had him worried that the world was getting out of control. After a short lecture I cut him off, confirming that he was not in fact a police officer, and politely assuring him that if the police wanted to talk to me about the bike they were welcome to. In hindsight it might have been interesting to try and ask him why he felt compelled to lecture me on the most minor infrigements of the Bicycle Safety Act, perhaps asking his thoughts on why helmets are not compulsory when there are so many other rules, or about the general cultural phenomena discussed in this post.

I understand this is a cultural difference and I don't want to offend anyone. I just think it would be great if people here were equally as forward when they had something nice to say.

MDS Talk

2009-06-08T20:55:00.004+02:00

This afternoon I gave a short talk at the RTG 'Methods for Discrete Structures' colloquium about a slight extension to some stuff from my Honours thesis. Here is the abstract:

First László Székely and more recently Saharon Shelah and Alexander Soifer have presented examples of infinite geometric graphs in the plane whose chromatic numbers differ depending if we (1) allow the axiom of choice as usual or (2) demand that the colour sets be Lebesgue measurable. The existence of such graphs may be relevant to the Chromatic Number of the Plane problem. In this talk I present some more graphs with this property which are also unit distance graphs, and hence may be seen as further evidence that the chromatic number of the plane might depend on set theory.

I just put the slides on my website.

Australien wieder im Fußball WM!!!

2009-06-07T09:21:00.004+02:00

That's right folks, this morning Australia sealed a place at the 2010 World Cup finals in South Africa by drawing 0-0 with Qatar. We have not conceded a goal in the 6 games so far of this 5 team qualifying group phase, and still have 2 games left to play. This is only our third world cup finals, but the second in a row after Germany 2006. The first was way back in 1974, also in (West) Germany. It is also our first finals as a member of the Asian Football Confederation after transfering from Oceania. Membership of the AFC gives us a more normal route to the finals with many group phase matches against quality sides, as opposed to previous campaigns where we played weak Oceania teams followed by a play-off against a South American or Asian side. Along with Japan, Australia has established itself as one of the strongest teams of the Asian confederation.

Euler Vorlesung

2009-06-06T09:52:00.003+02:00

Friday week ago the Berlin/Potsdam math communtity enjoyed the annual Euler Lecture in the theatre of the New Palace in Potsdam. This is the large palace at the western end of the Schloßpark Sanssouci. The main speaker was Prof. Hendrik Lenstra of the University of Leiden, and his talk on "Modelling Finite Fields" was very entertaining. The main idea was that, although mathematicians often talk of the finite field of order p^k, this field is only unique up to isomorphism. There are many possible models for the same field and if two people want to talk about some field they have to agree on a model first. He explained a way of choosing a 'canonical' model with some nice properties, such that translation between it and other models was reasonably easy. Of course, as well as a distinguished speaker, it was quite nice to hear a lecture in the unusual setting of the palace's theatre where Frederik the Great used to hang out.

New bike pics

2009-05-28T20:36:00.005+02:00

After much fooling around I finally got my fixed gear bike finished and ready to ride properly. Previously I said I would keep the drop handlebars that came with it and just add a brake lever, but after several test rides I decided I really didn't like the particular drops that came with the bike, and in general I didn't want drops because leaning down so low to grab them just made my neck hurt (or forced me to look at the ground, depending on how you look at it). So I bought some second hand triathlon bullhorns (Syntace Stratos with 40mm drop) off ebay and also a pair of reverse levers. Even though I had everything for two brakes I decided to go for just a front brake in the end because two was going to look real messy, and not make much difference to my maximum braking performance. This evening I went for a shakedown cruise along the Spree and it was really nice. Here are some photos I just took, though I probably should have waited for better light...

Laksa recipe - Part I

2009-05-24T16:25:00.010+02:00

Due to popular demand, I have finally got around to (beginning) to share my ideas on making Curry Laksa. As I have already bemoaned, Laksa is hard to come by in Berlin. Even commercial Laksa paste on which to base your Laksa - often a good way to go - is only available in one unsatisfying, and non-vegetarian brand. As an aside, if you can find a good asian grocer with lots of Laksa pastes, I recommend OSHA brand as it is tasty and vegetarian.

So why do we need Laksa paste? The paste contains all the spices that make your Laksa so tasty, and in the cooking process it is good to be able to fry all your spices together, so having them all in one paste is convenient. Also, it can make the cooking process more efficient as you can prepare paste for more than one meal and keep it aside for later use.

Here in Berlin I have made the paste in two ways. The quickest way was to base it on Thai Red Curry Paste which has quite a good subset of the necessary ingredients. However, I felt my more successful attempt was when I did the whole thing from scratch, so that's what I'll tell you about today.

LAKSA PASTE:

Ingredients:

1 head of garlic
1 red onion
3 thumb sized peices of galangal
8 candle nuts
2 large fresh chillies, deseeded
5 stems of lemon grass (use white part only)
8 tablespoons peanut oil
1 teaspon tumeric powder
1 tablespoon salt
1 teaspoon coriander paste
1 teaspoon Kings (Sri Lankan) curry powder
1 teaspoon peanut butter
1 red capsicum
rind of 1 lime

Notes:
Non-vegetarians would probably want to add shrimp paste. The onion can be replaced with shallots, especially asian shallots if you can get them. The curry powder was not your typical yellow 'curry' powder. It could be ommited or exchanged for some cumin. The salt is a matter of taste. Originally I put 2 tablespoons, but this was quite a lot and meant I didn't need stock powder in the soup later, so I'd try less. It may help as a preservative I guess. You could of course add more chilli, though I like to keep it mild (for spice intolerant guests) and serve with a good chilli sambal.

Method:
Now the obvious way to make a paste is with a powerful food processor, but I don't have one. Hence I developed a novel way to do it using what I had - a hand held food processor that couldn't chop these things by itself.

Begin by finely chopping everything. I mean fine! Then fry everything in a pan, using the peanut oil, until the capsicum is soft. Use a lid while frying to stop it drying out too much. It doesn't need to be blackened, just enough to get the flavours mixed together. Then you store the paste in the fridge and it's ready to use.

When you want to make a Laksa you take the paste you need and throw it in a container with the coconut milk you're going to use. With the extra liquid you can now use a hand held chopper thingo to blend the softened paste into a fine coconutty spicy mix. To hear how to make the whole Laksa you'll have to wait til next time.

Another day at the 'ring.

2009-05-21T19:55:00.004+02:00

It's that time of year again - this weekend is the 37th running of the 24hr race at Nürburgring Nordschleife. I won't be going this year, but I will be able to catch a bit on the TV. As usual there's a very long and varied entrants list. Interesting cars include a new GT3 spec Audi R8, the return of the Lexus LF-A prototype (with less camouflage this time), Corvette C6, Ford GT, Dodge Viper, Benz 190E Evo2, and of course many Porsches, BMW 3-series and Z4s and so on. What an amazing track - one day I'll drive there, one day.

Guitar

2009-05-18T10:24:00.005+02:00

As I hinted a while ago, I bought a guitar last year. I have played guitar since I was in primary school and until I went to Spain in 2001 I was most interested in blues and jazz on the electric guitar. However in Spain I took a few months of flamenco guitar lessons and since then I have mostly played flamenco-ish stuff on classical guitar.

Despite having guitars at home I didn't bring one with me to Berlin. It's a bit of a hassle/risk to take a guitar on the flight from Australia, so I decided it'd be best to buy one here. This was possibly not the best plan since it took me ages to get around to doing it, but all the while I was slightly frustrated by not being able to play. Even though I don't play many hours per week it's an important thing to help me relax and let out some emotional energy.

So being somewhat closer to Spain than normal I eventually formulated a plan to get a nice flamenco guitar. Though they look similar there are important differences between flamenco and classical guitars. Flamenco guitars are built to be especially loud and bright sounding, with fast attack and not so much sustain, and strong mid and treble response, without so much bass as a classical. This is acheived through the use of different woods, a thinner body and lighter construction.

My new guitar is a Soleá model from the workshop of Hermanos Sanchis López of Valencia, and it really is a fantastic instrument. The best praise I can give is to say that when I chose it I compared it to other guitars that cost up to three times more and I instantly felt that the Soleá sounded far better. I bought it from an online shop www.guitars.com.es, which despite seeming a bit risky, turned out to be an excellent idea. The guy from the shop actually recommended the model (which I then tested in a Berlin music shop) and gave me a good deal with a free case and other things chucked in.

Text to speech

2009-05-11T21:47:00.001+02:00

Another silly thing. What does a radiohead fan do with an online text to speech generator? Obvious.

How not to hold a 16kg cat

2009-05-02T18:19:00.004+02:00

I couldn't resist posting this pic.

More on the bike

2009-04-29T19:19:00.007+02:00

To recap, I bought a Fuji Track while I was in Melbourne. It's basically a nice chromoly frame with some fairly cheap components on it. I'll do an in depth review of the actual bike when I've ridden it a bit more. So far I only rode it a bit in Australia because it has no brakes. This is possible because of its fixed gear - the pedals are locked to the wheel so you can slow it down by resisting the pedals. However, the bike has a reasonably high gear ratio, so this is not very effective.

I brought it to Berlin by packing it myself into a box that I got from my local bike shop. This involved taking off the front wheel, handlebars and pedals, and then trying to pad the frame a bit with newspaper to prevent scratching. I then had to hope that the baggage handlers didn't kick it so much as to bend the wheels or anything. In the end the box was quite damaged, with holes made in it by the protruding axles, but was luckily not crushed out of shape, so the bike arrived fine.

It wasn't quite as easy as that though, because the box weighed 12kg and I also had a backpack, another bag with 9kg of clothes, a camera bag and a big coat to carry. This was possible but not that easy. Luckily I was helped along the way (thanks Susan and Moritz), and also used trolleys when available, so it wasn't so bad in the end.

For those who don't know, riding fixed is a bit of a fashionable thing at the moment. I'm not in it so much for the fashion as the attractive simplicity of a fixed gear single speed bike, and the purportedly different riding experience, which some claim brings the rider into 'greater harmony' with the bike and road. It certainly demands your attention more. I think this can be related to the design principle of my favourite automobile, the Mazda MX-5 (or Miata to some). This car is designed to give the purest driving experience possible, giving the driver an excellent feel for what the car and the road beneath are doing at all times - in japanese they called it "oneness between horse and rider". They succeded very well, and they did it by making the car simple. I think this is analogous to how a fixed gear bike feels compared to other bikes.

It turns out that being too simple can get you into trouble. The fashionable types have taken to riding these bikes without brakes, lights, or anything else that isn't completely necessary. This is of course against The Rules and a general threat to public safety and order. So it's not surprising that the Berlin police have joined in with those who love to hate on those who ride fixed, threatening to confiscate their immaculate machines.

I always planned to put brakes on mine, and have purchased some second hand calipers (A$20) and yesterday ordered some cyclocross style levers (20euro) which I'll mount on the top of my handlebars [bike talk: which are road drops in case you wondered. I considered changing to bullhorns with reverse levers, but decided to save the money and give the drops a proper go first.] In light of the attitude of the local Polizei I'll also add lights, reflectors, bells, whistles etc. up to the required amounts. I've even started wearing a helmet, which is rather stupidly the only thing that isn't mandatory.

The antipodal map

2009-04-27T21:24:00.002+02:00

That's some crazy action. Messes you up good. As mentioned before, I did it the hard way: Melbourne-Darwin-Singapore-Dubai-Hamburg-train to Berlin. As far as I am able to calculate in my weakened state, the door to door transit time was 41 hours. Left 11am April 26, arrived approx 8pm April 27 Berlin local time, with the time difference being +8 hours. So 24 + 9 + 8 = 41 right? Correct me if I'm wrong. Also, let me know about your marathon transits in the comments (I know Kaie has some good ones, especially in hrs/km terms.)

Highlights of the trip included visiting Darwin International Terminal (one large room with an annoying absence of a news agent from whom to purchase the NT News), going to Dubai (now I know I don't need to go back - the airport was plenty), chatting to a nice Indonesian girl on the Dubai-Hamburg flight who then helped me with my crazy luggage in exchange for help finding her way around Hamburg, and finally an extremely generous lift from Moritz from Hauptbahnhof to my place that saved much toil.

When I got home I built my bike (I couldn't wait to see who had won in Bike vs. Baggage Handlers. It seems that Bike did. More later.) Then I went down to the Turmstraße to get a recuperatory zucchinipuffer im brot mit käse. Berlin appears to me in a strange mix of newness and familiarity. I'm sure it won't last. Sleep time now.

Where is Michael?

2009-04-24T02:23:00.003+02:00

Why isn't he in his office working? Good question. The thing is, I'm still in Melbourne trying to work out how to get back to Berlin. I came to Australia on a Qantas staff ticket provided by my mum. These tickets only give you a seat when the plane isn't full, otherwise you get left behind. It turns out that right now things are busy for whatever reason, so I have little chance of getting on. For this reason I'm trying to work out the cheapest way of getting there on a real ticket, or perhaps a combination of pretend and real. Still, I should be back by Monday + epsilon.

Update: epsilon = 1 day. The current plan is to leave Sunday at 13:30 and fly Melbourne - Darwin - Singapore - Dubai - Hamburg (13:35 Monday), then train to Berlin. Total transit time: 34hr + train trip.

Another bike

2009-04-02T03:12:00.003+02:00

For a while I've been wondering what all the fuss about fixed gear bikes is, and while back in Melbourne I decided to take the opportunity to buy a basic track bike with the intention of taking it back to Berlin. I have barely any luggage to take back with me because my luggage coming here was almost all Nu's left over stuff. So since Qantas will carry bikes as part of the normal luggage allowance I figured I may as well buy one here where they are much cheaper than in Germany.

I bought a Fuji Track steel framed track bike. I've only ridden it a little so far because it came without brakes (because they're not needed in the velodrome). The frame seems good with threadless headset and sealed bottom bracket, but a few of the components are a little basic. The hubs are cheap Formulas with basic non-cartrige bearings. The rims are nothing fancy but seem straight and strong. It came with quite wide (700x28) tyres with a little tread which are probably a good choice for road use. Currently the front sprocket is a little off centre so the chain tension is not constant as the crack turns. I'm hoping I can adjust this out with a bit of fiddling. I'll write more once I've been for a proper ride.

Who will watch the Watchmen?

2009-03-30T01:59:00.002+02:00

Not me, not again. I went to the cinema last night for the first time in a long time and saw the graphic-novel-based film Watchmen. I have never been interested in comics, which probably explains why I can't ever remember liking a comic-based film, but this film seemed to me to really be complete rubbish. I am surprised to see that most online reviews are very positive, claiming that the film was dark, funny, thought provoking etc. It was certainly dark - quite violent and with plenty of grimy cityscapes. However the jokes were obvious and the dialogue contrived, and while it attempted to appear 'philosophical', for me it tended more to the nonsensical. The plot progressed ponderously, the film was far too long and the soundtrack was a mismatched mix of 60's music and other random stuff, in a film set in the 80's. No stars.

Back in Melbourne

2009-03-25T01:39:00.002+01:00

After flying out of Frankfurt on Sunday night I am now safely back in Melbourne. The flight went fine and I'm not feeling too bad with regards to jetlag. I only had a short stop over in Singapore, but the journey still took 33 hours from door to door. Luckily I was able to get some sleep on the plane, though not that much.

After a few days rest I will be getting stuck into the many things I want to do while here. I'll only stay for one month and I think its going to pass quickly because I have so much to do.

It's really nice to see Nu and my family again. Everything seems pretty much as it was when I left 18 months ago, and I think I'll settle in quickly.

Aprobado

2009-03-19T18:08:00.002+01:00

So I passed. This is good. I am happy, but taking things calmly as usual. The exam was more or less the kind of thing I was expecting, and the 90 minutes passed pretty quickly. I managed to stay nice and calm through the exam too, which was always part of my strategy. No point panicing.

Now I've got to pay attention to all the things I've been ignoring, like housework, a new housemate moving in, and the fact that I'm going to the other side of the world on Sunday. I'll spend about 4 weeks at home, then it's back to Berlin to begin Phase II. I'm looking forward to actually doing some research at last!

The decline of maths in Australia

2009-03-04T11:32:00.000+01:00

The mathematical scene in Berlin is large and active and I am very happy to have come to Berlin. I've heard some picky people say things like 'yes, but it's mostly applied...' or whatever, but this doesn't detract from the fact that there is a huge amount of activity and opportunities here. I'm sure there are plenty of other places around the world that are as good or better, but when I compare Berlin to what we have in Australian, well there is almost no comparison to be made.

Maths in Australia seems to be in trouble, from primary teaching all the way to academic research. There have been a number of articles about this recently, as there has just been some review paper released I think. See this blog post by Terry Tao on the Maths in Australia Blog, and the links to newspaper articles.

The problems seem to be: the school curriculum is rubbish, the school maths teachers are underpaid and underqualified, the qualified ones go elsewhere where they are paid fairly, the university departments are underfunded and shrinking, no one gets the point of studying maths, etc.

I quite liked this article by a former lecturer at Monash, who taught me a nice course in Measure Theory.

What do I want from a national curriculum? I want a dodecahedron in every classroom, and beautiful diagrams to ponder. I want students to know why there are infinitely many prime numbers, and for them to realise no one knows about twin-primes. I want them to know what the golden mean is, and why it is irrational, and why we care. I want pattern and play and beauty. And I want the times tables.
Is teaching any of the above useful? It is exactly as useful as teaching Harry Potter and Shakespeare.

Apart from grouping Rowling with Shakespeare, I think he's spot on.

4 weeks to go

2009-02-19T22:10:00.000+01:00

Classes and minor exams are over, and I now have exactly 4 weeks left before my qualifying exam (the date was changed to March 19). I'm feeling cautiously optimistic about the process. I know more or less what material I have to master for the exam, and am now revising and summarising it on little cards. Historically my exam preparation skills have been pitiful, so this represents a big step for me. Hopefully my methods will work.

The exams I did last week should be the last course exams I do since in 'Phase II' we are not required to take assessment for the courses we do. The qualifying exam should in some sense be the last normal exam I do, which is a nice thought. There should hopefully be a thesis defence at some stage which would resemble an exam, though it's somehow different since you should know your thesis pretty well by default.

Vegetarianised

2009-02-13T13:40:00.000+01:00

I have been almost vegetarian for a long time due to living with vegetarian Nu, and since her birthday last November I've been really actually vegetarian. So far it's been good and I intend to continue. It's funny to think, but it seems that a huge proportion of our friends are vegetarian too, so I wonder what the actual statistics are. At least in Germany it must be relatively uncommon, as suggested by this article that appeared in The Age. Come on Germans! Give the pigs a break:

Germans are among the highest meat consumers in Europe, obtaining around 39 per cent of their total kilojoule intake from meat and meat products, compared with 25 per cent in Italy.

To be fair, our travels to Spain last summer showed that country to be much less vegetarian friendly than Germany. At least here people are well aware of what it means to be vegetarian, which didn't always seem to be the case in Spain. Being forced to eat tortilla every meal somewhat tainted Nu's experience of the country, which was sad since I rather hoped she'd like it.

Nu ist weg

2009-02-08T11:54:00.000+01:00

Many things have been happening recently, but due to Lockdown conditions I have not been blogging. Here are a few updates.

On Saturday Nu left for Sri Lanka where her brother is soon to be married, and in a couple of weeks will head home to Melbourne with her family. She called this morning to say that she had arrived safely and that the weather is of course lovely and warm.

Of course I'm sad that Nu is gone and the house is very quiet without her. Luckily I will be able to see her again in about 6 weeks when my qualifying exam is over and I go home for a break. I'll only stay for a month though, and after that there will again be sad goodbyes.

I will have to stay in Berlin probably for another 3 years to finish my PhD, though I will be able to visit home occasionaly, perhaps even for academic purposes. Nu on the other hand needs to study one more year at Monash to finish her Bachelor of Arts and then intends to do an extra year for the 'Honours' degree which is necessary for postgraduate study.

In other news, my home state of Victoria is ablaze, with huge losses of property and so far 84 people confirmed dead. These fires may well be the worst in our history, and are certainly the worst since the 'Ash Wednesday' fires of February 1983, just after I was born.

Also, the last BMS Friday of the semester inlcuded a nice talk by Gil Kalai from the Hebrew Uni of Jerusalem. Gil also spent some time in our research group and was an examiner at the thesis defence of my colleague Ronald Wotzlaw. Congratulations to Dr Ronald for finishing!

Hitting the Laksa spot

2009-01-10T22:50:00.000+01:00

A few weeks ago I made a first attempt at a batch of homemade laksa paste. I made enough to last us a while and so far we've used it three times. The first was with Moritz and it came out reasonable well, though perhaps a bit too thick with coconut milk and a little heavy on the paste. The one after that was a bit too watery but the one I made tonight really hit the spot. I made a spur of the moment decision to make a small supper laksa to use up a half can of coconut milk we had in the fridge. I just had some onion, carrot and mushroom stir fried in the pot, then I chucked in the paste and the coconut, and once it was boiling poured in a beaten egg. Lastly I added some boiling water and cooked noodles and a bit of a stock cube and it was ready to go. It turned out to be an absolute ripper. The egg worked really well and the soup was just right, especially after adding a good amount of our favourite chilli-garlic sambal. Some photos and a detailed recipe will follow soon.

¡LOCKDOWN!

2008-12-28T17:24:00.000+01:00

To pass to the doctoral phase of the BMS program I have to take an oral qualifying exam, and generally it should be at the end of this my third semester. Thus I have pencilled in the date of Friday 13 March (very lucky) in the hope that I can also squeeze in a trip home to Melbourne before class starts again in mid April.

The exam is meant to last 90 minutes and cover three topics with three examiners. In my case they will be Geometry (Springborn), Commutative Algebra (Schmitt) and Polytopes (Ziegler). Following venerable traditions from my undergraduate years I have declared a period of 'lockdown' until the exam. This means I will not go out much and try to study as much as possible, and only things related to the exam. The last two things are normally the ones I have most trouble with. I'm a terrible procrastinator, and even when I do sit down to do maths, for some stupid reason I often find the least relevant things the most interesting to think about. I'll probably also start sporting a lockdown beard to save on shaving time and might alter my sleeping pattern to rise early and study in the morning.

Another part of my lockdown program is to do regular exercise. Since Nu and I joined the TU gym we have been going quite often, and even now that the gym is closed for two weeks over christmas, we're still working out a bit at home (with Nu's beloved Tae Bo videos). I think this is helpful for my concentration in general. For Nu it has produced quite a radical change. Before she was quite lethargic a lot of the time and often slept during the day. It certainly didn't seem that she had the energy for lots of exercise. Funnily enough she now seems to be filled with energy and genuinely enjoys the workouts.

Alle Schönste Semester: Status Report

2008-12-07T12:35:00.000+01:00

The alle schönste semester has so far been a partial success. Addressing each of the points in the original post:

I have unfortunately been mainly doing homework sheets and not getting much extra maths work done. However since I volunteered to present something in the Polytopes class this is forcing me to do a bit of reading.
We did join the gym and it's been fun so far. I forgot how nice it was to do some exercise occasionally.
I still haven't made Laksa again, but don't despair, it's coming.
Neither of us have done as much guitar playing/painting as we should.
We are hosting couchsurfers, and so far it's been lots of fun and not too much of a burden on our time.
We did go to one of the ancient history museums (in fact the one with the famous bust of Nefertiti, or "that woman from the cover of my year 7 history book"). We plan to try to see more museums, maybe on Thursday nights when I'm told there's free entry.
Nu enjoyed her SKB Deutsch Kurs, but I'm as hopeless as ever.
I got my army coat, and it's fairly warm but quite baggy.

It is now about 2 months until Nu leaves and I can see we are going to be super busy for the rest of the time. She has several philosophy essays to write and I will be busy trying to get organised for my qualifying exam which I must plan for the not too distant future. If we are lucky we'll squeeze in one more little trip to Dresden or Prague over the christmas break.

After Nu leaves I will have to do something about my accomdation - either get a flatmate to share the apartment or move somewhere else. In any case it will be a bit of a hassle and I'm not looking forward to it.

Somewhere down the line I want to go home to Australia for a break too. I hope I can squeeze this in to the winter break (mid-Feb to mid-April), but with the exam as well this could be hard.

BMS Friday 11

2008-11-29T13:50:00.000+01:00

Last BMS Friday's talk was given by Prof. Wolfgang Lück of Münster, who incidentally will soon be replacing Prof. Ziegler as president of the DMV (German Mathematical Society). He gave a talk on the Borel conjecture, which states that two aspherical closed manifolds are homeomorphic if their fundamental groups are the same. Prof. Lück has been involved in some recent progress regarding this conjecture and his talk was a nice summary of the present situation and the relationships between related conjectures. His slides are available here.

After the main seminar there was again a 'What Is...' Seminar this time given by Barbara Jablonska. She gave a nice talk on knot theory with lots of really cool computer visualisations.

The Laksa Revolution

2008-11-09T17:52:00.000+01:00

Lots of people in Berlin have been talking about an impending culinary revolution and the establishment of Laksa as a broadly available and popular dish here. Berlin's large transient population has been exposed to many and varied influences and it is unsurprising that after contact with this delicious noodle dish in the wider world they should yearn to be able to buy it here. For those of you who haven't yet tried it, you can get some idea of what it's all about on wiki, or perhaps at delaksa.com. Essentially it's a spicy Malaysian/Singaporean noodle soup dish with coconut milk and typically seafood, though chicken or vegetarian versions are possible.

So far I have found only one place in Berlin serving Laksa, namely Amy's Malaysian Restaurant at Wilmersdorfer Str. 79 (but now it may have closed - see comments). In the photo you can see me trying it. It was quite good, but not exactly like the one's I was used to in Melbourne. Still, Amy is actually Malaysian, so who am I to argue. There may be other possibilities for finding Laksa in Berlin; investigations are ongoing and positive results will be reported. If you know of any places, please let me know in the comments! (Since writing I have tried the Laksa at 'Asia Gourmet' in Hauptbahnhof. It was quite tasty, but again not really Laksa as I know it. The search continues.)

Laksa is much easier to come by in Melbourne. Its popularity means that it is not only available from Malaysian restaurants (though these are generally the best), but also from general Asian fast food places and often in Chinese and Thai restaurants. Also, my local Asian grocery store back in Clayton stocked around 8 different Laksa spice pastes for the home-Laksa afficionado. Importantly, this large variety of pastes included vegetarian versions, since shrimp paste is a common ingredient in many pastes. The paste is a mix of chilli, shallots, galangal, lemongrass, candle nuts, lime peel and other spices, so it's much easier to buy it pre-made than make it yourself.

Homemade Laksa in Berlin is another story. The best Asian grocery store I know of is in Mullerstrasse near the Seerstrasse U-bahn (in the basement under Lidl). Even this large store only has one type of Laksa paste which isn't vegetarian, and to my taste isn't very good. Since making the paste from scratch is so time consuming I have tried basing it on Thai Red Curry paste which has quite a large subset of the ingredients needed. This was reasonably successful and can be seen in the second photo. I plan to do a few more trial runs in the coming months to improve on these efforts, and finally present the finished result by having some friends over to try it.

Das alle schönste Semester

2008-11-01T20:30:00.000+01:00

Plans are afoot for an attempt at having the alle schönste Semester this semester. Last semester was a bit of a fizzer for Nu, so to keep her from despairing completely I've convinced her to have a serious crack at having some fun before she leaves (see her account). She has embraced the idea and is mostly doing quite well.

My plans for a good semester include the following:

Lots of maths: Hopefully some time for more than just homework sheets.
Sport: We claim we want to join the gym.
Laksa party: To my dismay this spicy Malaysian dish has not taken a hold here. Maybe you don't think Laksa is a big thing, but then again, you probably didn't know it has it's own global franchise. The battle to establish Laksa in Berlin has just begun. Join me if you dare.
Art: Rumour has it that I purchased a guitar (more on that some other time). Hopefully I will find time to play it, and Nu will do some of her painting, especially finishing her crazy coffee table.
People and couches: Our travels got us all enthusiastic about couchsurfing. We met some awesome people and we know there is a huge couchsurfing community in Berlin ready to be explored.
Berlin: There is so much to see and we have seen so shamefully little.
Deutsch: Nu is going to classes at the TU SKB (a good place for Deutsch classes by the way). I decided not to, but I still intend to make some effort to learn the basic grammar of which I am so totally ignorant.
Warmth: A better coat will improve the enjoyability of the winter months. I'm already feeling the cold and its only autumn as far as I know.

BMS Friday 10

2008-11-01T11:37:00.000+01:00

This week's BMS Friday included two talks. The first was the main talk given by Prof Martin Skutella of the TU about network flow problems. It was the first talk since a set of instructions for the presenters was drafted by the students in an attempt to make the talks of a more even standard, at least partly accessible to all. In this case the instructions worked very well and the talk was quite readily understandable. Prof Skutella explained some older results on static flows through a network (graph) where each edge has a specified capacity and the aim is to find the maximum possible amount of flow from a specified source to a sink. Then he discussed ways the problem could be generalised to include the time dimension, by giving each edge a transit time and asking how much flow could pass in a certain time. There were some very nice computer simulations included at the end too.

After this talk the 'What is ... Seminar' which I have mentioned before was held for the first time as part of BMS Friday. The plan is for this to occur at each BMS Friday (normally fortnightly), and for the What Is Seminar to be held elsewhere in other weeks. This week's topic was Homotopical Algebra presented by my TU colleague Anton Dochtermann. This is very loosely something like an abstract axiomatisation of homotopy theory somewhat analogous to axiomatic homology theory. It builds up a category theoretic description of what a homotopy theory is with standard homotopy theory appearing as an instance. I would say this was quite an advanced talk for a What Is Seminar, but there was a good turnout and I think most of us took at least something away, especially if we had done a little algebraic topology. Anton's exposition was as always relaxed and enjoyable.

Semester III

2008-10-29T19:18:00.000+01:00

I am starting my third Semester at the BMS, and in theory it should be the last one as a 'Phase I' student. After the usual experimentation I have settled on three courses, only two of which I really need to do. They are Commutative Algebra (Schmitt), Analysis and Geometry on Manifolds (Ecker), and Discrete Geometry II (Ziegler).

Ecker's course is a little outside my main area of interest, but I am happy to do it because I actually did a bit of that sort of stuff in undergrad (it was one of the few areas Monash was ok for) and also because Ecker is a good lecturer. In fact he was formerly a lecturer at Monash and though he left just before my time, I knew of his reputation from other students.

Ziegler's course is the one I don't really need to do, but I'm attending it out of interest. Its devoted to discussing open problems mainly related to polytopes. I sort of volunteered to present something on one of the problems. It goes something like this: All 3-polytopes can be realised with rational (equivalently integer) vertices, but there are 4-polytopes that cannot. The question asks if there are any cubical 4-polytopes that cannot. Cubical means each face is combinatorially a cube. I think the reason to study cubical polytopes is that they are somehow the next case after simplicial ones. Simplicial polytopes can always be realised with rational vertices because we can perturb their vertices without breaking the faces. So does cubicality give us the 'rigidity' we need to build irrational polytopes?

After this semester I should take the qualifying exam and hopefully proceed to phase 2. Still only a handful of people have taken the exam, but it's nice to see that most of them manage to do ok. I will be discussing arrangements for my exam with Prof Z soon. I'm not even sure what subjects I'll do it on, though I'd guess it'll be Geometry, Topology and Polytopes.

Parents Visit

2008-10-29T19:05:00.000+01:00

After travelling with my parents through Spain a few weeks ago, it was again a pleasure to have them around for about a week when they visited Berlin. I hadn't seen them for a year and won't see them again until some time next year. We did a few nice things together with Nu, most notably going out to Potsdam (for the first time!) to see the palaces and park. At almost 60 this was my dad's first trip to Europe and in his own unpredictable way (actually quite predictable if you know him) he decided it would be a good idea to bring my soft toy monkey (Rover) from when I was a boy and take it on a grand tour. Hence most of his photos involve the monkey rather than us. He claims that some friend of his is going to post a website of Rover's travels, so I will link to it if it actually eventuates.

BMS Friday 9

2008-10-17T20:43:00.000+02:00

In first semester I managed to write something about each BMS Friday lecture I attended. This custom was surreptitiously abandoned in second semester (partly due to truancy), but I will try to reinstate it. The first lecture of the semester was by Norbert Schappacher and aimed to demonstrate the influence of politics in mathematics. Many would think that maths, being the purest of sciences would be immune to such influence, but this is not completely true. Now I'm no crazy postmodernist, so I would say that mathematical truth is independent of politics, but unfortunately the process of doing maths, as carried out by imperfect humans, certainly isn't. Schuppacher's talk told the story of some question of algebraic geometry posed by Kronecker. Later a chief Nazi mathematician (whose name I forget) gave an example which answered the question, only for it to be attacked later by an anti-Nazi and apparently shown to be wrong. In the end it seems that the question could be understood in a particular way (using much more recent theories) that made the Nazi's example work. The moral was that it can be quite hard to pin down the truth, and people are apt to take sides for non-mathematical reasons.

Volver

2008-10-11T00:36:00.000+02:00

After a year living in Europe I finally returned to my point of reference, Spain. I have lived in Spain for two extended streches in the past. First in 2001 I spent a year in Salamanca going to high school on an exchange program, living with a host family and learning a lot of Spanish. Later in 2004 I returned as a university exchange student for a semester to study philosophy and spanish for my arts degree in the Universidad Autónoma de Madrid.

This time I went as 'tour guide' for Nu and my parents for about two weeks roaming from place to place. In brief, we went to Sevilla for a couple of days, then Granada for a couple more, then Madrid for a night to drop in to the Prado Museum, then to Salamanca, including the sierra town of La Alberca, then we hired a car for four days in Galicia and toured the green hills and small fishing towns before leaving from Santiago de Compostela.

I had a great time even though the only places I hadn't been before were Sevilla and Galicia. Granada, and Andalucía in general fascinate and enchant me for reasons that are hard to describe, and I'm sure I will return again before long. It was also lovely to catch up with my host family in Salamanca, and to explore Galicia.

I did find something to dislike about spain though - the extremely homogenous and carnivorous food culture. This made finding food for vegetarian Nu a bit of a nightmare, and at one stage she said that she'd vomit if forced to eat eggs again.

Travels

2008-09-16T19:52:00.000+02:00

I've just finished a series of backdated posts about our 3 week holiday in greece so check them out if you're interested - they all have the 'greece' label. I will probably add a few choice photos to the posts soon. Next week we're off again to Spain with my parents too, so that should be fun.

Dice

2008-09-14T20:56:00.000+02:00

Last Thursday I gave a talk in our group's mittagsseminar on some things related to the chromatic number of the plane problem. When you take the intersection of the Voronoi cell of a lattice with a ball that cuts off it's vertices you get something that we call a 'polytopal die'. Dave Coulson and I used such a shape in our paper about large distance excluding sets in 3-space. I found out recently that such a set also arises when one looks for large sets of a given diameter which avoid the non-zero points of a lattice. I think I might write up a short article about the connection between these problems, so let me know if you're interested.

Phillip Island 6hr Regularity Trial

2008-09-02T23:19:00.000+02:00

Last weekend by brother drove our car in a 6 hour regularity trial at the Phillip Island moto GP track. In a regularity trial you get points for doing laps in a time close to a target time that you fix at the start. Because it's not technically a race you can do it on a level 2S Cams permit. It was a team relay event with teams having several cars and drivers, and only one car on the track at a time. My brother was in a team of 4 red NA MX-5s. Our car is in the foreground and you can see two more of the team cars in the background. Note the cool Nordschleife sticker above the exhaust.

Nu has a bath

2008-08-31T11:51:00.000+02:00

On Friday Nu had a few too many G&Ts while having her bath, cut her hand with a breadknife while making lunch, fainted and hit her head and got stitches in her hand at the local surgery (see her account). Now she's an invalid and I have to help her with everything, despite my terrible head cold. Here are some quotes from this morning...

"It's time for my bath! I'll need music." (to drown out the carnival noises)

"Can you get the shower head down?... ok," (turns on tap with shower head pointing up from bath tub and is surprised when water shoots out of the bath) "I can't do it with one hand!"

Now in bath:

"Get me a tissue... now weave it through my fingers on my bad hand, it stops them feeling sweaty... not like that, fold it in half!"

"Michael, one of my candles is out!" (I relight it, but the tealight candles are almost finished).

"Now three of my candles are out!!!" (I replace them all).

"I'm cold! Come and dry me!"

Getting dressed:

"Now you gotta roll up my sleeves... oh that's not neat enough."
Me: "That's what you're getting."
"Fine... what's for lunch?"

Cheap Berlin Furniture

2008-08-30T16:32:00.000+02:00

After (long after) the success of our furniture hunting mission of late February I always planned to put up some links and info for anyone looking for cheap furnishings in Berlin. Most people think of Ikea when they think of cheap furniture, but we didn't just want cheaper than other furniture furniture, we wanted really actually cheap (or free) furniture. We invested in 5 days of van hire (220euro from Sixt) in the hope that we would recover the cost in other savings. Since delivery of Ikea stuff could easily run to 100euro it wasn't too much to expect.

Transport is at a premium in Berlin where most people have a small car or no car at all, so if you have the wheels to carry it there is a lot of free/cheap stuff on offer if you know where to look.

One good word to know is Haushaltsauflösung, meaning moving house sale. Different people expect different things when they have these - some still want you to pay a bit too much for their crappy stuff, but you'll find others where everything really has to go quick and you can get some bargains.

Our main successes came from the following sources:

The newspaper Zweitehand. It comes out about 3 times a week (ask your newsagent) and includes furniture sections and a general giveaway section. It can be helpful to get it nice and early like 7am and call people as soon as you think they'd be awake
Kijiji is a pretty good site for online classifieds and if you check it regularly you can find some good stuff.
BSR-verschenkmarkt is a site just for people to give away free stuff. We got a couple of good things here.

Other possiblities are:

Sozialladen are something like an op-shop. The one in Neuköllnische Allee 114 had some ok furniture at reasonable prices.
Twins Company is an ok second hand furniture shop, but they're there to make a profit, so not especially cheap. For household furniture you want the store in Lichterfelde.

Another random tip: if you're after large rugs to cover your floors, try a carpet shop such as Domäne. There you can find large offcuts sold at a discount. We got a 3m by 4m carpet for about 30euros.

In the end the gamble of hiring the van paid off very well. Here is a list of the kind of prices (in euro) we paid:

Set of couches - free
Desk - free
Chest of drawers - free
Coffee table - free
Microwave - 25
Dinner table seats ten - 50
8 chairs - 30
TV stand with wheels and drawer - 20
Metal double bed with old matress - 30
1 year old mattress - 50 (cost 240 new)
68cm Grundig TV - 50
5m x 4m 'persian' rug - 30

Flippin' Carnival Folk

2008-08-29T17:10:00.000+02:00

This weekend it appears we have the Turmstrassefest (for the second time since we moved in) and so the street is filled with flippin' carnies. They've erected all manner of kitschy stalls and 'amusements' and are now blasting us with layers of random music accompanied by shouting kids. Somehow it's more annoying than the usual traffic noise. At least they stop reasonably early unlike the traffic.

Backsliding

2008-08-26T20:23:00.000+02:00

I'm back in the Big B after 3 weeks in Greece. I've many tales to tell, so I'm going to take advantage of blogger's feature that let's you backdate posts to pretend that I blogged as I went. Check below this post in the next few days.

As for now, I'm really tired and in need of a damn good wash. For the next month I'm planning to work hard on some maths before going to Spain with Nu and my parents.

Santorini and Paros

2008-08-21T18:38:00.000+02:00

After leaving Crete we headed to the spectacular but highly visited island of Santorini. It's a half-ring shape formed by the rim of an old caldera and has some volcanically active islands in its centre. The small population and tourist oriented nature of the island meant that couchsurfing was not an option so we stayed in a hostel. This was only my second time staying in a youth hostel (after Granada a few years ago). It was sort of funny that almost all the people staying in the place were Australians. It certainly wasn't as rich an experience as couchsurfing, but we had fun. One day we did a tour on a boat to visit the volcano island in the centre of the caldera. Another day we hired a car and toured around a bit, visiting a winery and seeing some of the interestingly coloured volcanic rock beaches.

After Santorini we continued to the more relaxed island of Paros. Here we couldn't couchsurf either and ended up in a nice rented room. By now we were well and truly in relax mode and not looking for anything too strenuous. Nu had also developed a strange reaction to the sun (a sort of rash) and was trying to avoid the sun as much as possible. With the brilliant sunshine every day and high temperatures this was a bit difficult. At this stage our budget was on 'limp home mode' so we just ate sandwiches made from fresh vegies and feta cheese and drank a bottle of Ouzo over a few days. We really got a taste for Ouzo and have taken to drinking it from time to time back at home. It's great because it's somewhere between a hard spirit and a liqueur in that it has slightly sweet taste without being sirupy.

Cretans aren't so bad

2008-08-17T20:24:00.000+02:00

Bad pun, sorry. But really, we had a great time in Crete, though come to think of it we didn't meet many Cretans, and no cretins. We couchsurfed again, this time staying with a guy who lived in a tiny village in the mountains above Chania. He was originally from Thessaloniki and had made his way to the Cretan highlands after getting fed up with Athens. His place was very basic but very peaceful. He grew delicious vegies in his garden, and there were also many wild fruit trees throughout the village. The pears and figs were wonderful. Goes to show how good fruit and veg can tast when grown naturally. The general high quality of the produce we enjoyed in Greece has made Berlin's fruit and veg even more disappointing.

The main problem we had with life in the Village was that it was hard to get around the Island. We really should have hired a car and our problems would have been solved. Since we didn't all we really got to see was the pretty city of Chania (which has a beautiful venetian harbour) and a mediocre beach in a tourist strip. Next time we'll know better. Our last night on Crete was spent in Iraklio from where we took the ferry to Santorini.

Monasteries in the Air

2008-08-12T18:55:00.000+02:00

Leaving Volos we headed to the famous monasteries of Meteora in the centre of mainland Greece. We spent an afternoon seeing them and a night in the nearby town of Kalabaka. The monasteries really are an amazing site, entirely due to their location. They're perched atop some amazing rocky pillars in a fascinating mountain range. Not being religious we weren't particularly interested in the interiors of the monasteries, which was lucky since we only had time to see one. I said to Nu at the time that the mountains were so amazing that they would be a significant attraction even without monasteries built on impossibly small peaks.

After taking a taxi to the highest monastery and looking inside we walked back down to town. This was a good plan except that the only place to walk seemed to be the road. This reminds me of one qualm I had with Greece - there didn't seem to be any walking trails anywhere we went.

Volos & Tsipouro

2008-08-11T18:06:00.000+02:00

Tsipouro is not a town but a drink somewhat similar to Ouzo. While in Volos our wonderful host and his friends showed us how to relax in the local manner, drinking Tsipouro accompanied by fresh and tasty local food. This really was a fantastic couchsurfing experience. We wouldn't necessarily have guessed it would be so good from the start. After arriving quite late in Volos by train we met our host, a 30-something year old civil engineer living in a typical bachelor pad. It was messy and filled with the most amazing collection of gadgets, travel books and other collectibles. Soon we were introduce to his lovely friends including his girlfriend who is also a couchsurfer.

The first major outing we had was to drive up into the nearby Mount Pilio to have a coffee in one of the beautiful villages overlooking the city of Volos. Then on the weekend we drove to a beach on the other side of the peninsula and camped for the night. There we had dinner in a rustic beachside tavern, again drinking Tsipouro and listening to some local musicians playing bouzouki, accordion and singing. We even befriended some drunken friends of the bouzouki player.

This was the kind of great experience of local life that would seem to be virtually impossible without something like couchsurfing. It was also a great example of how you often have the most fun when you're least expecting it.

To Volos via Delphi

2008-08-10T12:30:00.001+02:00

From Athens we took a bus to the ancient crossroads of Delfi where the oracle sat, the different city-states had treasuries and there was a large temple dedicated to Apollo. It was also the site of the Pythian Games which predated the Olympic games. The archeological site was very large and we spent several hours exploring it under the hot sun. There was a pleasant breeze at times, and at the end of our stop we took a quick look through the airconditioned museum which held many of the statues and other artifacts found in the site.

That night we had arranged to stay with another couchsurfing host in the city of Volos, some 300km north of Athens. We didn't realise this at the time, but the transport network in Greece in essentially radial with all major routes passing through Athens. This meant that the 200km journey from Delphi to Volos would require two busses, a train, a detour to Larissa and about 7 hours. Our host summed it up - 'you sure chose a strange way to come to Volos'. We were just happy to have made it.

Ye Olde Athens

2008-08-08T17:35:00.000+02:00

Our tour of Greece began in Athens on the 3rd. As Nu had already been doing for the last few weeks, we couchsurfed instead of staying in paid accomodation. Couchsurfing is an online community of people who offer to host each other when travelling, and my first couchsurfing experience was really good. I arrived on a flight in the evening and found our hosts house without much trouble. Nu however came on a very late flight from Bratislava and had to find her way there at about 4am. Of course she had managed to run out of phone credit and ended up having to ask strangers for help to find the obscurely marked street. She got there in the end though.

We spent four nights in Athens and spent our time seeing the ancient sites and museums. It was pretty damn hot especially around the early afternoon when most people would be resting in the shade, but we mostly soldiered on. The ancient sites were really cool. I especially liked the ruins of the ancient Agora where Socrates once quizzed the citizens with his elenchus. Of course the Acropolis was also amazing, and the huge National Archeological Museum was fascinating, but too much for a single visit.

As for the rest of Athens, we didn't see much of it, but it wasn't particularly alluring, especially in the intense heat. What we did see was a bustling, crowded and rather run down city. The roads in particular were eye-opening with hordes of motorbikes, frantic traffic, cracking pavement and an almost total lack of paint markings.

One interesting thing was that my knowledge of the Greek alphabet that I have from studying maths was reasonably helpful in letting me sound out Greek words. Nu and I both found the Greek language very interesting. I was surprised at just how many words that I considered as being latin really had roots in Greek.

You are my centre as I spin away...

2008-08-07T19:41:00.000+02:00

I'm finally getting into 'In Rainbows'... here's Videotape:

--------------
When I'm at the pearly gates
This'll be on my videotape

When Mephistopheles is just beneath
And he's reaching up to grab me

This is one for the good days
And I have it all here
In red blue green

You are my center when I spin away
Out of control on videotape
On videotape

This is my way of saying goodbye
Because I can't do it face to face
So I'm talking to you after it's too late
From my videotape

No matter what happens now
I won't be afraid
Because I know today has been the most perfect day I've ever seen
--------------

Loving someone is one of the greatest things we can do in life. When we look back, our days of love are the ones we remember most vividly, with the most nostalgia. I think this song is about a wonderful day of love.

I've listened to it (actually the album version) a lot recently and it's confirmed yet again what I have long known - Radiohead are the standout group of the last two decades. Words can't express the awe and appreciation they inspire.