%0 Journal Article
%T Cremona transformations and diffeomorphisms of surfaces
%A J¨˘nos Koll¨˘r
%A Fr¨¦d¨¦ric Mangolte
%J Mathematics
%D 2008
%I arXiv
%X We show that the action of Cremona transformations on the real points of quadrics exhibits the full complexity of the diffeomorphisms of the sphere, the torus, and of all non-orientable surfaces. The main result says that if X is rational, then Aut(X), the group of algebraic automorphisms, is dense in Diff(X), the group of self-diffeomorphisms of X.
%U http://arxiv.org/abs/0809.3720v2