Friday, March 30, 2007

Tables of Numbers

Usually I try to excuse myself from arithmetic reponsibilities, explaining that, contrary to popular understanding, maths is about the manipulation of greek letters, rather than the manipulation of actual numbers. We mathematicians tend to leave the latter to accountants.

In spite of this, I have been working hard lately to write code to compute some actual numbers for me. Garden variety calculators (even the fancy graphing kind) won't produce these numbers for me. There are some calculators for mathematicians that will do this sort of computation. See, for example:



What I'm trying to produce here are some numbers which determine certain kinds of modular forms. My code will eventually produce modular forms that even William Stein's lovely calculator doesn't (yet) find for me. In the meantime, I'm just trying to get it to work in the cases where I already have data to compare with mine. I finally got it to match up with some old tables of numbers from John Cremona. Here's a small sample:



The numbers in the table are eigenvalues for simultaneous eigenvectors for the matrices giving the action of Hecke operators T_p, where the p are, for example, the primes you see in the left hand column. (These are primes in the Gaussian integers.) The congruence subgroup in question here is Gamma_0(N) where the level N is given in the top row.

Getting my numbers to match up with his is like a return to the good old days when doing math included that so very satisfying part where you match your answer up with the one in the back of the book.

Sunday, March 25, 2007

Update

Where, you ask, is Flat Stanley? After dancing with the druids, he had been planning to spend some time in Regent Street and Leicester Square. I was supposed to get him back from Severine last night when I met up with her and a couple of other friends from our Chinese class for dinner. But it turns out that Severine is a much better Flat Stanley host than I; she's now taking him to Scotland next week!

I should be flat and made out of paper.

Saturday, March 24, 2007

read me

Tuesday, March 20, 2007

Support Ken & Chris!

Ken and Chris are doing a half marathon in June to raise money for Leukemia research. We get over 80 people at Thanksgiving yet very few of those 80 people are on the list of supporters. Admittedly, some may have chosen to donate anonymously, but my guess is that most, like myself, had been meaning to donate and just hadn't gotten around to it. I finally did, and I'm a poor graduate student. So you can too. If all 80 of us each donate $100, we'll blow past their fundraising goal. It's easy. Just go to their donation website:

http://www.active.com/donate/tntwhv/tntwhvCTorrey