J. Buzzi, O. Sester, M. Tsujii
Weakly expanding skew-products of quadratic maps
(44K, LateX 2e)

ABSTRACT.  We consider quadratic skew-products over angle doubling of 
the circle and prove that they admit positive Lyapunov exponents almost 
everywhere and an absolutely continuous invariant probability measure. 
This extends corresponding results of M. Viana and J.F. Alves for 
skew-products over linear strongly expanding map of the circle.