John Baez’s Week 235 of This Week’s Finds in Mathematical Physics is out. This week he talks about quantum computing, and his work on higher gauge theory.
Archive for July, 2006
Baez Week 235
Saturday, July 15th, 2006More on Grothendieck topologies
Thursday, July 13th, 2006If you’re comfortable with the language of schemes and representable functors, you can find a nice introduction to Grothendieck topologies here: Notes on Grothendieck topologies, fibered categories and descent theory, by Angelo Vistoli.
Extra Dimensions in Physics
Sunday, July 9th, 2006Bee at Backreaction has written the definitive weblog post on the experimental search for evidence of the existence of extra dimensions. (One consequence of string theory, if it’s true, is the existence of additional dimensions beyond four.)
Freese on Universal Algebra
Saturday, July 8th, 2006A few universal algebra links, collected by Ralph Freese. (Universal algebra is the branch of mathematics that studies generalizations of groups, rings, and algebras. The hallmark of each family of objects that can be studied by universal algebra is that it satisfies a version of Noether’s isomorphism theorems.)
Wikipedia on Grothendieck topologies and topos theory
Wednesday, July 5th, 2006Another triumph for Wikipedia. Every time I do a web search, I’m impressed with the progress Wikipedia is making. Check out their dry but complete summary of Grothendieck topologies, and their more evocative Background and genesis of topos theory.
Big Bang Bad?
Sunday, July 2nd, 2006Rob Knop thinks that the Big Bang is a bad name for a good theory. Read this post on his weblog for more. If astronomers ever do decide to drop the name Big Bang, I hope they return to Lemaitre’s original name for the concept: the primordial atom. It has a 20s-science-fiction/evil-scientist sound to it. You can just imagine Bela Lugosi saying, “The fools. They laughed at me, but they’ll laugh no more once I have harnessed the power of the primordial atom”.