We prove that C-infinity diffeomorphisms of a two-dimension manifold M
with a homoclinic tangency are in the closure of an open set of Diff(
infinity) (M) containing a dense subset of diffeomorphisms exhibiting
infinitely many coexisting Henon-like strange attractors (or repellers
). A similar statement is posed in terms of one-parameter C-infinity f
amilies of diffeomorphisms unfolding a homoclinic tangency. Moreover,
we show the existence of infinitely many dynamical phenomena others th
an strange attractors. (C) Elsevier, Paris.