Foliations and minimality for twist maps

Abstract

In this paper we consider area-preserving twist maps $f:\mathbf{T}^2\to\mathbf{T}^2$ with vertical rotation sets reduced to a single irrational number $\alpha$. Our first result states that under these hypotheses, there exists a $f$-invariant foliation $\mathcal{F}_G=\{\operatorname{Graph}(\phi_t)\}_{t\in\mathbf{T}^1}$, where each function $\phi_t:\mathbf{T}^1\to\mathbf{T}^1$ is $K$-Lipschitz for some constant $K=K(f)$. Moreover, we also prove that in case $\mathcal{F}_G$ is a Lipschitz foliation and the leaf dynamics, which is always a transitive circle homeomorphism of rotation number $\alpha$, is bi-Lipschitz conjugate to the irrational rotation $R_{\alpha}$, then $f$ is minimal.