SOME CONTACT BIFURCATIONS IN TWO–DIMENSIONAL EXAMPLES

In this paper we consider some properties of two-dimensional noninvertible maps, which possess a chaotic attractor. Contact bifurcations causing a qualitative change in the shape of chaotic attractors, or causing their destabilization, have been considered in several papers since the early work in 1978 [19]. Such contact bifurcations, due to the contact between the boundary of a chaotic attracting set or area, and the boundary of its basin of attraction, may involve a fuzzy (or chaotic) basin boundary. In the examples considered in this paper we shall see that such bifurcations correspond to homoclinic bifurcations of repelling cycles of the map (repelling nodes, foci or saddles).