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.
Original language | English (US) |
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Pages (from-to) | 44-61 |
Number of pages | 18 |
Journal | Advances in Mathematics |
Volume | 222 |
Issue number | 1 |
DOIs | |
State | Published - Sep 10 2009 |
All Science Journal Classification (ASJC) codes
- General Mathematics
Keywords
- Automorphism group
- Diffeomorphism group
- Mapping class group
- Rational surface
- Real algebraic surface