Scott Aaronson and Greg Kuperberg have put together a website, the Complexity Zoo, that describes 443 (!) computational complexity classes.

Scott Aaronson and Greg Kuperberg have put together a website, the Complexity Zoo, that describes 443 (!) computational complexity classes.

I mentioned this to my colleagues in Computer Science working in computational complexity, and one estimate was that the Complexity Zoo has only about 10% of all the complexity classes so far identified in the literature!!!

There are really 4000 known complexity classes?