Abstract
We study outer automorphism groups Out(ℛ) of equivalence relations ℛ arising from ergodic, essentially free and measure-preserving actions on standard probability spaces of mapping class groups, and compute them explicitly for some examples. We show that the subgroups of Out(ℛ) associated with action-automorphisms are always finite index ones. Moreover, a sharp upper bound of the indices among all such actions of mapping class groups is obtained.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have