Published online by Cambridge University Press: 04 May 2017
In this paper we investigate maps of the two-torus $\mathbb{T}^{2}$ of the form
$T(x,y)=(x+\unicode[STIX]{x1D714},g(x)+f(y))$ for Diophantine
$\unicode[STIX]{x1D714}\in \mathbb{T}$ and for a class of maps
$f,g:\mathbb{T}\rightarrow \mathbb{T}$, where each
$g$ is strictly monotone and of degree 2 and each
$f$ is an orientation-preserving circle homeomorphism. For our class of
$f$ and
$g$, we show that
$T$ is minimal and has exactly two invariant and ergodic Borel probability measures. Moreover, these measures are supported on two
$T$-invariant graphs. One of the graphs is a strange non-chaotic attractor whose basin of attraction consists of (Lebesgue) almost all points in
$\mathbb{T}^{2}$. Only a low-regularity assumption (Lipschitz) is needed on the maps
$f$ and
$g$, and the results are robust with respect to Lipschitz-small perturbations of
$f$ and
$g$.