Combinatorics Seminar - Marc Lackenby

16:00-18:00

Speaker: Marc Lackenby

Title: Unknot recognition in quasi-polynomial time

Abstract: I will outline a new algorithm for unknot recognition that runs in quasi-polynomial time. The input is a diagram of a knot with n crossings, and the running time is 2^{O((log n)^3)}. The algorithm uses a wide variety of tools from 3-manifold theory, including normal surfaces, hierarchies and Heegaard splittings. In my talk, I will explain this background theory, as well as explain how it fits into the algorithm.