Speaker
Radu Saghin
(PUCV)
Description
We consider a family of area preserving non-invertible maps on the two-torus, which is the composition of the well-known Chirikov standard family ($s_r$) with a linear expansion $E$. If $E$ is an homothety then our family can be seen as a "randomized" version of the standard family. We show on one hand that the Lyapunov exponents are different for all small values of $r$. On the other hand, for large enough expansion and values of the shear parammeter $r$, we also obtain lower bounds for the difference between the two Lyapunov exponents.
We will discuss ome possible generalization.
This is joint work with Martin Andersson, Pablo Carrasco and Jiagang Yang.
