Simultaneous renormalization of commuting circle diffeomorphisms
Abstract
We define a renormalization operator for pairs of commuting orientation preserving circle diffeomorphisms of class C3. The operator is driven by the accelerated Brun multidimensional continued fraction algorithm. For rotation vectors of simultaneously bounded type, under a summable strong convergence condition satisfied by all eventually periodic types with Pisot period matrix, the renormalizations converge exponentially fast in C2 to pairs of rigid rotations. The pair is simultaneously C1+γ conjugate to the pair of rotations, with γ>0 depending only on the bounded type constant. A fast renormalization extends exponential convergence and C1 rigidity to a class of rotation vectors of full Lebesgue measure, containing explicit vectors outside bounded type. We show that the operator is topologically hyperbolic. The partition of the renormalized pairs by rotation vector is an invariant lamination whose leaves are the topological conjugacy classes. All results hold for pairs of class C2+α.
Related
- On C2 circle diffeomorphisms with rotation numbers of constant type
- Dimension theory of group actions by circle diffeomorphisms I: Stationary measures
- Codimension-one holomorphic Anosov diffeomorphisms
- A Ballantine-Type Factorization of Diffeomorphisms
- On the Topological Transitivity of Interval Extensions of Anosov Diffeomorphisms
BibTeX
@misc{petkovic2026simultaneous,
title = {{Simultaneous renormalization of commuting circle diffeomorphisms}},
author = {Boris Petković},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.05049},
eprint = {2610.05049},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.05049},
}
RIS
TY - UNPB
TI - Simultaneous renormalization of commuting circle diffeomorphisms
AU - Boris Petković
PY - 2026
DA - 2026/10/04
PB - arXiv
DO - 10.48550/arxiv.2610.05049
UR - https://arxiv.org/abs/2610.05049
AB - We define a renormalization operator for pairs of commuting orientation preserving circle diffeomorphisms of class C^3. The operator is driven by the accelerated Brun multidimensional continued fraction algorithm. For rotation vectors of simultaneously bounded type, under a summable strong convergence condition satisfied by all eventually periodic types with Pisot period matrix, the renormalizations converge exponentially fast in C^2 to pairs of rigid rotations. The pair is simultaneously C^1+γ conjugate to the pair of rotations, with γ>0 depending only on the bounded type constant. A fast renormalization extends exponential convergence and C^1 rigidity to a class of rotation vectors of full Lebesgue measure, containing explicit vectors outside bounded type. We show that the operator is topologically hyperbolic. The partition of the renormalized pairs by rotation vector is an invariant lamination whose leaves are the topological conjugacy classes. All results hold for pairs of class C^2+α.
ER -