My virtual spaces

End of the semester & Toric geometry problem

2009-01-29T14:36:00.007+01:00

My second semester as a grad student at UU has ended (quite successfully) and hopefully I will have a topic for my thesis and an advisor by next week. Really looking forward to that!

A more or less interesting problem I have encountered during one of the courses I took was the following:

(This is a toric variety associated to some semi-lattice S)

Now we are given some element of our vectorspace and want to check whether it is actually in V. This is not as simple as it looks in the first place:

So far, I've not come up with a general method for deciding whether such a point is contained in V or not. For some special cases it is not difficult to prove that checking the condition for only the basis of M and some (finitely many) more elements of M is enough, although I don't know if in general, checking a finite number of equations suffices.

How many?

2008-11-26T23:38:00.004+01:00

Yesterday, I was wondering with a friend how many mathematicians there are on the globe (where we defined a mathematician as someone who has published a mathematical paper over the las ten years, and curiously enough cut ourselves out). Our first estimation was something like 1000000 but I have not been able to find some reliable figures on the net to confirm it. However, I did stumble upon this during my search which really made me laugh hard, although I've heard quite a few mathematical jokes in the past four years.

Utopia

2008-11-13T09:23:00.004+01:00

This is one of the best pranks I've seen in years. According to www.spiegel.de, roughly 1.2 million copies of this "New York Times Special Edition" have been distributed in the bigger cities of the US. A pdf of the paper is available on their site, the download's really worth it, even if you just read the headlines and look at the ads!

Assimilation

2008-10-31T14:39:00.005+01:00

It's starting to get cold here.... doesn't keep me from taking the bicycle though. I feel pretty Dutch on these occasions ;)

Update: What does keep me from taking the bike is a chain that corroded and ruptured due to harsh weather conditions. Hmpf...

Stupid

2008-10-17T11:58:00.006+02:00

I fixed a problem just to create many many new ones. Note to myself: NEVER EVER DO rm -R ~/.kde AGAIN.

Arrgh, one month of e-mail conversation have just passed away. At least amarok works now...

The blessings of a CAS

2008-10-12T22:39:00.004+02:00

Although I hardly use a computer in my daily math routine, I'm sometimes more than glad they exist. Today, I saved approximately 2 hours of painful calculations by using the excellent CAS sage to factor some polynomials over finite fields and solve some systems of linear equations, instead of doing it by hand.

Poor 19th-century number theorists!

PS: sage is free! try it!

Traded Data for CD

2008-10-10T17:04:00.002+02:00

I regularly take part in online surveys for some market research company. For each survey I complete, they give me a certain amount of credit points. Once I have gathered enough of them (that usually happens once every year), I can trade in points for Amazon vouchers. This time I got a CD and a book. I hope they will distract me from thinking about what will happen to my data ;)

First posting

2008-10-10T13:24:00.001+02:00

This is my second attempt at maintaining a blog. Expect postings about math, music, Holland and anything else. Don't expect daily updates ;)