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Dimension theory of group actions by circle diffeomorphisms I: Stationary measures
Abstract
We establish a structure theorem for smooth random walks on the circle and study the dimensional properties of their stationary measures, including exact dimensionality and a Ledrappier-Young-type dimension formula. These results provide the technical tools needed for the main theorems in Part II "Dimension theory of group actions by circle diffeomorphisms II: Minimal sets". They also yield an approximation theorem in the spirit of Katok, Avila-Crovisier-Wilkinson, and Morris-Shmerkin, together with a time-reversal symmetry for circle actions: every semigroup T contained in Diff+1+Ξ±(π1) without finite orbits has the same number of minimal sets as its inverse semigroup Tβ1.
Related
- Exact dimensionality of stationary measures for random diffeomorphisms with all Lyapunov exponents equal and negative
- Absolute continuity of invariant measures for random diffeomorphisms
- Finitely generated groups of diffeomorphisms with prescribed critical regularity in every dimension
- Stationary kinetic Krylov-Safonov estimates in space dimension one
- Finite Borel asymptotic dimension of bounded-to-one commutative monoid actions
BibTeX
@misc{he2026dimension,
title = {{Dimension theory of group actions by circle diffeomorphisms I: Stationary measures}},
author = {Weikun He and Yuxiang Jiao and Disheng Xu},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.13254},
eprint = {2610.13254},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.13254},
}
RIS
TY - UNPB
TI - Dimension theory of group actions by circle diffeomorphisms I: Stationary measures
AU - Weikun He
AU - Yuxiang Jiao
AU - Disheng Xu
PY - 2026
DA - 2026/10/09
PB - arXiv
DO - 10.48550/arxiv.2610.13254
UR - https://arxiv.org/abs/2610.13254
AB - We establish a structure theorem for smooth random walks on the circle and study the dimensional properties of their stationary measures, including exact dimensionality and a Ledrappier-Young-type dimension formula. These results provide the technical tools needed for the main theorems in Part II "Dimension theory of group actions by circle diffeomorphisms II: Minimal sets". They also yield an approximation theorem in the spirit of Katok, Avila-Crovisier-Wilkinson, and Morris-Shmerkin, together with a time-reversal symmetry for circle actions: every semigroup T contained in Diff_+^1+Ξ±(π^1) without finite orbits has the same number of minimal sets as its inverse semigroup T^β1.
ER -