English

Topological expansive Lorenz maps with a hole at critical point

Dynamical Systems 2024-05-14 v1

Abstract

Let ff be an expansive Lorenz map and cc be the critical point. The survivor set is denoted as Sf(H):={x[0,1]:fn(x)H,n0}S_{f}(H):=\{x\in[0,1]: f^{n}(x)\notin H, \forall n\geq 0\}, where HH is a open subinterval. Here we study the hole H=(a,b)H=(a,b) with acba\leq c \leq b and aba\neq b . We show that the case a=ca=c is equivalent to the hole at 00, the case b=cb=c equals to the hole at 11. We also obtain that, given an expansive Lorenz map ff with a hole H=(a,b)H=(a,b) and Sf(H){0,1}S_{f}(H)\nsubseteqq\{0,1\}, then there exists a Lorenz map gg such that S~f(H)Ω(g)\tilde{S}_{f}(H)\setminus\Omega(g) is countable, where Ω(g)\Omega(g) is the Lorenz-shift of gg and S~f(H)\tilde{S}_{f}(H) is the symbolic representation of Sf(H)S_{f}(H). Let aa be fixed and bb varies in (c,1)(c,1), we also give a complete characterization of the maximal interval I(b)I(b) such that for all ϵI(b)\epsilon\in I(b), Sf(a,ϵ)=Sf(a,b)S_{f}(a,\epsilon)=S_{f}(a,b), and I(b)I(b) may degenerate to a single point bb. Moreover, when ff has an ergodic acim, we show that the topological entropy function λf(a):bhtop(fSf(a,b))\lambda_{f}(a):b\mapsto h_{top}(f|S_{f}(a,b)) is a devil staircase with aa being fixed, so is λf(b)\lambda_{f}(b) if we fix bb. At the special case ff being intermediate β\beta-transformation, using the Ledrappier-Young formula, we obtain that the Hausdorff dimension function ηf(a):bdimH(Sf(a,b))\eta_{f}(a):b\mapsto \dim_{\mathcal{H}}(S_{f}(a,b)) is a devil staircase when fixing aa, so is ηf(b)\eta_{f}(b) if bb is fixed. As a result, we extend the devil staircases in \cite{Urbanski1986,kalle2020,Langeveld2023} to expansive Lorenz maps with a hole at critical point.

Keywords

Cite

@article{arxiv.2311.02465,
  title  = {Topological expansive Lorenz maps with a hole at critical point},
  author = {Yun Sun and Bing Li and Yiming Ding},
  journal= {arXiv preprint arXiv:2311.02465},
  year   = {2024}
}

Comments

18pages

R2 v1 2026-06-28T13:11:39.511Z