On generic G-prevalent properties of C^(r) diffeomorphisms of S¹ and a quantitative K-S theorem

We will consider a convex unbounded set and certain group of actions $G$ on this set. This will substitute the translation (by adding) structure usually consider in the classical setting of prevalence. In this way we will be able to define the meaning of $G$-prevalent set. In this setting we will show a kind of quantitative Kupka-Smale Theorem and also a result about rotation numbers which was first consider by J.-C. Yoccoz (and, also by M. Tsujii).