Videos

Hot Topics: Artin Groups and Arrangements - Topology, Geometry, and Combinatorics: "Giving a quadratic solution for the word problem in 3-free Artin groups"

Presenter
March 14, 2024
Keywords:
  • Artin groups
  • braid groups
  • Coxeter groups
  • reflection groups
  • Garside structures
  • classifying spaces
  • hyperplane arrangements
  • subspace arrangements
  • configuration spaces
  • geometric group theory
  • Matroids
  • cohomology
MSC:
  • 14N20
  • 20F36
Abstract
We will explain a method of rewriting words that allows us to obtain geodesic representatives for elements in Artin groups that do not have a relation of length 3 and, as a direct consequence, we will solve the word problem in this (big) family of Artin groups. Our techniques are based on detecting a certain type of words, which we call critical, and defining from them transformation rules that we call tau-moves. In particular, we show that in every non-geodesic word there is a sequence of tau-moves that ends with a reduction in the word. Additionally, we provide a recursive method to apply these sequences, so that we obtain an algorithm with quadratic complexity in the length of the input word. This is a joint work with Rubén Blasco-García and Rose Morris-Wright.