Basins of periodic orbits for elliptic maps of the torus

The behavior of basins of periodic orbits, for families of elliptic maps in the 2D torus depending on a parameter, is studied. We give an explicit formula for periodic orbits (i.e., central points of basins), considering also the occurrence of singular situations. Such a formula describes the evolution of basins, showing that onset and disappearance of periodic orbits cannot be reduced to a simple bifurcation scheme. Also, the stochastic features of the strange attractor at the border of ellipticity may be related to the dynamics of collapsing basins.