Cohomological equations and invariant distributions for minimal circle diffeomorphisms
arXiv:1002.3392 · doi:10.1215/00127094-1345662
Abstract
Given any smooth circle diffeomorphism with irrational rotation number, we show that its invariant probability measure is the only invariant distribution (up to multiplication by a real constant). As a consequence of this, we show that the space of real smooth coboundaries of such a diffeomorphism is closed if and only if its rotation number is Diophantine.
32 pages. Revised version after referee report. To appear in Duke Mathematical Journal