Complexity Theory: Now a Path to Enlightenment

I’ve been insanely busy lately, which means I have a gigantic backlog of stuff that I meant to link to, but didn’t.

Scott Aaronson has a knack for taking certain interesting but not obviously revolutionary inspiring concepts in complexity theory and in good Russian-formalist fashion, making them strange. Here are some examples:

  • The Fable of the Chessmaster suggests that a perfect chess master could demonstrate their mastery to a high degree of certainty without revealing their strategies. Scott goes on to suggest that we can think of complexity theory as “mathematical theology” :-)
  • Logicians on safari connects complexity to super-intelligent aliens, the Riemann hypothesis to your car trunk, and that the fact that your computer crashes once a second is no excuse for not finishing your work.
  • More tender nuggets points out, among other things, that if babies can learn languages by example alone, they can also learn to break RSA.

Math Stranger than Fiction

I just saw the movie Stranger than Fiction, and I noticed a strange pattern in the last names of characters: Pascal, Hilbert, Escher, Cayley, Mittag-Leffler. Also, the main character’s favorite word is “integer”. The main character has a penchant for counting, but other than that the movie is as far removed from mathematics as can be imagined, so it’s all very mysterious.

December Notices

The December Notices of the AMS are out. The two features articles are:

This month’s What is a… Quasiconformal Mapping introduces a generalization of conformal mappings that makes sense in general metric spaces.

The Illusory Unity

I will be out of town for a few days for Thanksgiving, so there won’t be any posts from me for the next few days.

Mathematical textbooks take pains to make their subject appear to form a unified whole. Is any such unity an illusion? Discuss.

Kalman Filter

A friend of mine who’s studying econometrics asked me about the Kalman filter, which is used in estimating the parameters of a time series model. I didn’t know anything about the subject, so I was poking around online, where I discovered that the Kalman filter is rocket science: it was invented to estimate the current position and trajectory of the Apollo spacecraft. And here I thought the only concrete result of the space program was Tang.