English

Dynamics of piecewise increasing contractions

Dynamical Systems 2021-03-16 v2

Abstract

Let I1=[a0,a1),,Ik=[ak1,ak)I_1=[a_0,a_1),\ldots,I_{k}= [a_{k-1},a_k) be a partition of the interval I=[0,1)I=[0,1) into kk subintervals. Let f:IIf:I\to I be a map such that each restriction fIif|_{I_i} is an increasing Lipschitz contraction. We prove that any ff admits at most kk periodic orbits, where the upper bound is sharp. We are also interested in the dynamics of piecewise linear λ\lambda-affine maps, where 0<λ<10<\lambda<1. Let b1,,bkb_1,\ldots,b_k be real numbers and let Fλ:IRF_\lambda: I\to \mathbb{R} be a function such that each restriction FλIi(x)=λx+biF_\lambda|_{I_i}(x)=\lambda x +b_i. Under a generic assumption on the parameters a1,,ak1,b1,,bka_1,\ldots,a_{k-1},b_1,\ldots,b_k, we prove that, up to a zero Hausdorff dimension set of slopes λ\lambda, the ω\omega-limit set of the piecewise λ\lambda-affine maps fλ:xIFλ(x)(mod1)f_\lambda:x\in I \mapsto F_\lambda(x)\pmod{1} at every point equals a periodic orbit and there exist at most kk periodic orbits. Moreover, let E(k)\mathfrak{E}^{(k)} be the exceptional set of parameters λ,a1,,ak1,b1,,bk\lambda,a_1,\ldots,a_{k-1},b_1,\ldots,b_k which define non-asymptotically periodic ff, we prove that E(k)\mathfrak{E}^{(k)} is a Lebesgue null measure set whose Hausdorff dimension is large or equal to kk.

Keywords

Cite

@article{arxiv.2007.08014,
  title  = {Dynamics of piecewise increasing contractions},
  author = {José Pedro Gaivão and Arnaldo Nogueira},
  journal= {arXiv preprint arXiv:2007.08014},
  year   = {2021}
}

Comments

20 pages, 2 figures

R2 v1 2026-06-23T17:09:13.059Z