Diffeomorfismi birazionali del piano proiettivo reale

  • Thierry Vust

    Université de Genève, Switzerland
  • Felice Ronga

    Université de Genève, Switzerland


We study real birational transformations of the real projective plane which are diffeomorphisms. It turns out that their degree must be congruent to 1 mod 4, and that they are generated by linear automorphisms and transformations of degree 5 centred at 3 pairs of conjugated imaginary points. Our approach is inspired by recent proofs of the classical theorem of Noether and Castelnuovo that use the Sarkisov program.

Cite this article

Thierry Vust, Felice Ronga, Diffeomorfismi birazionali del piano proiettivo reale. Comment. Math. Helv. 80 (2005), no. 3, pp. 517–540

DOI 10.4171/CMH/24