16:00
A cap set is a subset of Fn3 with no solutions to x+y+z=0 other than when x=y=z, or equivalently no non-trivial 3-term arithmetic progressions. The cap set problem asks how large a cap set can be, and is an important problem in additive combinatorics and combinatorial number theory. In this talk, I will introduce the problem, give some background and motivation, and describe how I was able to provide the first progress in 20 years on the lower bound for the size of a maximal cap set. Building on a construction of Edel, we use improved computational methods and new theoretical ideas to show that, for large enough n, there is always a cap set in Fn3 of size at least 2.218n. I will then also discuss recent developments, including an extension of this result by Google DeepMind.