Exponential mixing for heterochaos baker maps and the Dyck system

TL;DR

This paper studies the mixing properties of generalized heterochaos baker maps and the Dyck system, proving exponential mixing and mixing of all orders in various settings, which enhances understanding of complex dynamical systems.

Contribution

It introduces new classes of piecewise affine non-Markovian maps, proving their exponential mixing and mixing of all orders, extending previous results to more complex systems.

Findings

Maps are mixing of all orders.

Exponential mixing established for maps with mostly expanding or contracting centers.

Exponential mixing shown for the Dyck system with two ergodic measures.

Abstract

We investigate mixing properties of piecewise affine non-Markovian maps acting on $[0,1]^2$ or $[0,1]^3$ and preserving the Lebesgue measure, which are natural generalizations of the {\it heterochaos baker maps} introduced in [Y. Saiki, H. Takahasi, J. A. Yorke. Nonlinearity 34 (2021) 5744-5761]. These maps are skew products over uniformly expanding or hyperbolic bases, and the fiber direction is a center in which both contracting and expanding behaviors coexist. We prove that these maps are mixing of all orders. For maps with a mostly expanding or contracting center, we establish exponential mixing for H\"older continuous functions. Using this result, for the Dyck system originating in the theory of formal languages, we establish exponential mixing with respect to its two coexisting ergodic measures of maximal entropy.