Signature morphisms from the Cremona group over a non-closed field
Stéphane Lamy
Université Paul Sabatier, Toulouse, FranceSusanna Zimmermann
Université de Toulouse and Université d'Angers, France
Abstract
We prove that the plane Cremona group over a perfect field with at least one Galois extension of degree 8 is a non-trivial amalgam, and that it admits a surjective morphism to a free product of groups of order 2.
Cite this article
Stéphane Lamy, Susanna Zimmermann, Signature morphisms from the Cremona group over a non-closed field. J. Eur. Math. Soc. 22 (2020), no. 10, pp. 3133–3173
DOI 10.4171/JEMS/983