Infinite Ergodic Theory Workshop: Abstract Mariusz Lemańczyk

Mariusz Lemańczyk
Title: Invariant measures for Rokhlin cocycle extensions and non-singular joinings

Abstract: I will present a theorem (joint result with F. Parreau) which describes invariant measures (projecting on μ) for extensions T_φ,S of an automorphism T acting on (X,B,m) of the form

T_φ,S(x,y)=(Tx,S_φ(x)(g))

where φ:X→ G is a cocycle and S=(S_g)_g∈G is a Borel action of G on a Borel space Y. Relations with non-singular ergodic theory and some applications will be shown.