Cremona transformations and diffeomorphisms of surfaces
Algebraic Geometry
2009-06-08 v2 Geometric Topology
Abstract
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.
Cite
@article{arxiv.0809.3720,
title = {Cremona transformations and diffeomorphisms of surfaces},
author = {János Kollár and Frédéric Mangolte},
journal= {arXiv preprint arXiv:0809.3720},
year = {2009}
}
Comments
17 pages, 11 figures, shorter proofs and improvement of the results