On recurrence sets for toral endomorphisms

Zhangnan Hu, Tomas Persson

Published 2025-01-20Version 1

Let $A$ be a $2\times 2$ integral matrix with an eigenvalue of modulus strictly less than 1. Let $T$ be the natural endomorphism on the torus $\mathbb{T}^2=\mathbb{R}^2/\mathbb{Z}^2$, induced by $A$. Given $\tau>0$, let \[ R_\tau =\{\, x\in \mathbb{T}^2 : T^nx\in B(x,e^{-n\tau})~\mathrm{infinitely ~many}~n\in\mathbb{N} \,\}. \] We calculated the Hausdorff dimension of $R_\tau$, and also prove that $R_\tau$ has a large intersection property.