The spectral gap for transfer operators of torus extensions over expanding maps

Jianyu Chen, Huyi Hu

We study the spectral gap for transfer operators of the skew product $F:{\mathbb{T}}^d\times {\mathbb{T}}^{\ell }\to {\mathbb{T}}^d\times {\mathbb{T}}^{\ell }$ given by $F(x,y)=(Tx, y+τ(x) \pmo…