English

Rotation number and dynamics of 3-interval piecewise $\lambda$-affine contractions

Dynamical Systems 2025-10-09 v3

Abstract

We consider a family of piecewise contractions admitting a rotation number and defined for every x[0,1)x\in[0,1) by f(x)=λx+δ+dθa(x)(mod1)f(x)=\lambda x + \delta + d \theta_a(x) \pmod 1, where λ(0,1)\lambda\in(0,1), d(0,1λ)d\in(0,1-\lambda), δ[0,1]\delta\in[0,1], a[0,1]a\in[0,1] and θa(x)=1\theta_a(x)=1 if xax\geq a and θa(x)=0\theta_a(x)=0 otherwise. In the special case where a=1a=1, the family reduces to the well studied ``contracted rotations" xλx+δ(mod1)x\mapsto \lambda x + \delta \pmod 1, which are 2-interval piecewise λ\lambda-affine contractions when δ(1λ,1)\delta\in(1-\lambda,1). Considering a(0,1)a\in(0,1) allows maps with an additional discontinuity, that is, 33-interval piecewise λ\lambda-affine contractions. Supposing λ\lambda and dd fixed, for any ρ(0,1)\rho\in(0,1) and α[0,1]\alpha\in[0,1], we provide the values of the parameters δ\delta and aa for which the corresponding map has rotation number ρ\rho, and a symbolic dynamics containing that of the rotation Rρ:[0,1)[0,1)R_\rho:[0,1)\to[0,1) of angle ρ\rho with respect to the partition given by the positions of 1ρ1-\rho and α\alpha in [0,1)[0,1). This enables in particular to determine the maps that have a given number of periodic orbits of an arbitrary period, or a Cantor set attractor supporting a dynamics of a given complexity.

Keywords

Cite

@article{arxiv.2501.16263,
  title  = {Rotation number and dynamics of 3-interval piecewise $\lambda$-affine contractions},
  author = {P. Guiraud and M. Hernández and A. Meyroneinc and A. Nogueira},
  journal= {arXiv preprint arXiv:2501.16263},
  year   = {2025}
}

Comments

45 pages, 7 figures

R2 v1 2026-06-28T21:20:10.141Z