Signature morphisms from the Cremona group over a non-closed field
Algebraic Geometry
2021-10-08 v2 Group Theory
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 two.
Cite
@article{arxiv.1707.07955,
title = {Signature morphisms from the Cremona group over a non-closed field},
author = {Stéphane Lamy and Susanna Zimmermann},
journal= {arXiv preprint arXiv:1707.07955},
year = {2021}
}
Comments
Statements only over perfect fields instead of arbitrary fields (see Remark 1.3). A few other minor corrections