Cycle-maximal triangle-free graphs

Thursday 30 October 2014, 12:16

In January of 2011, I had recently arrived at the University of Manitoba to work as a postdoc with Stephane Durocher. One of the first things he asked me to do was find out how many cycles there are in an n-dimensional hypercube graph, for general n. At the time, he and I both assumed that that meant spending maybe half an hour in the library looking up the answer.

Since then it's been more than three years; thousands of lines of computer code and months of CPU time; we added two more co-authors; we didn't solve the original problem, and didn't completely solve the other problem that we ended up working on, either; but here's a journal paper, anyway, and I think it's pretty interesting. The official definitive version will be free to access until mid-December and then will go behind Elsevier's paywall; the authors' accepted manuscript on arXiv is permanently accessible.

Read the paper if you're interested in the math details; in this entry I'm going to try to tell the story behind the paper, in relatively non-mathematical terms. I'm hoping it'll be of interest to my Web log readers and give you some idea, because I often get asked this, of what I actually do at work.

Days since last Biblical plague: 0

Wednesday 15 October 2014, 11:49

Every time I think I've seen it all with regard to Danish excuses, this place surprises me. Today's excuse is tzaraath.

False negative

Monday 6 October 2014, 12:26

I. Fukurou

Bank Account Man

Saturday 4 October 2014, 13:23

I've been in Denmark just over a month, and I'm pretty stressed. This update is going to be somewhat disconnected. You can get some idea of what my experience has been like by watching the famous Bank Account Man commercial.

The Danish excuse list

Thursday 4 September 2014, 12:35

Denmark, being part of Europe, has a great deal of bureaucracy and many rules. However, the Danes are not really rule-followers. That at least is their reputation among people from other Nordic countries and I can see why. This is a list of excuses I've heard from Danish people, mostly government bureaucrats. All are genuine, though some have been paraphrased from their more complicated original forms or to remove personal information. The list will be periodically updated.

A few days in Denmark

Thursday 4 September 2014, 12:32

As I start writing this, it's Thursday aboput 2pm in Copenhagen, and I am in the waiting room at International House Copenhagen, waiting to apply for a Central Persons Register (CPR) number. I have been in Denmark since Monday morning.

Heading for Denmark

Thursday 28 August 2014, 18:59

I don't think I have officially mentioned this here on my Web log yet, but here it is: I am moving to Denmark to work as a postdoc in the Scaleable Similarity Search project at the IT University of Copenhagen. This is a one-year temporary position with a possible renewal for a second year.

As I type this, I am in my apartment in Winnipeg, sitting on top of my modular synthesizer in its Pelican case because that is the closest thing to furniture that hasn't been taken away by either the movers or Goodwill.

The Apollo moon landings were fake

Sunday 20 July 2014, 20:20

The Apollo moon landings were fake.

I don't mean that they did not occur - it was before I was born, but it seems clear that men did at one time walk on the Moon. There are too many independent confirmations of that for it to be in any reasonable doubt. However, the Apollo Moon landings occurred under false pretences. The story told about the factual events, both at the time and now, was and is a dishonest story, carefully constructed to further the goals of the US government and certain other powerful forces.

Don't plagiarize your cover letters!

Monday 10 February 2014, 08:39

The text below pretty much speaks for itself. Bold highlighting and numbered footnotes in [square brackets] are mine; all the rest is as I received it. Some irregularities of spacing and punctuation, visible in the original email, aren't obvious in the HTML. Names of the students are redacted because (after finding several more copies on the Web) I imagine the students are relatively innocent victims of bad advice. Name of the institution not redacted because I hope others who receive such letters and look for them on the Web will be able to easily find this posting.


Friday 13 December 2013, 13:09

TeXとLaTeXで画を書いたらTikZは便利とポピュラーです。 みんなはきれいなグラフィクスを作っています。 たとえば、これがtexample.netから一つのクリスマスツリーです。


しかし、ただのグラフィクスには興味ありません。 今日は1984年からノスタルジックの画を書きましょう。 マック・ペイントを思い出しませんか? そう…