Videos

Homomorphisms from Random Walks

Presenter
September 23, 2011
Keywords:
  • geometric group theory
  • geometric measure theory
  • Cayley graphs
  • quantitative geometry
  • probability theory
  • random walks
  • entropy formulas
MSC:
  • 60Gxx
  • 60-xx
  • 46-xx
  • 46Bxx
  • 46B06
  • 46B09
  • 46B20
  • 46B80
Abstract
I will discuss a construction of homomorphisms from finitely generated groups G to the reals R coming from random walks on G. If the square of the drift grows faster than the entropy, one can get a nontrivial such homomorphism. One consequence is that if G lacks nontrivial homomorphisms to R or if the random walk is symmetric of finite second moment, then one has that the entropy must dominate the square of the drift, even in cases where the Varopoulos-Carne bounds are not available. Some further variants of this construction and consequences may be discussed. This is based on joint work with A. Erschler.