English

Bijective Cremona transformations of the plane

Algebraic Geometry 2022-03-22 v4

Abstract

We study the birational self-maps of the projective plane over finite fields that induce permutations on the set of rational points. As a main result, we prove that no odd permutation arises over a non-prime finite field of characteristic two, which completes the investigation initiated by Cantat about which permutations can be realized this way. Main ingredients in our proof include the invariance of parity under groupoid conjugations by birational maps, and a list of generators for the group of such maps.

Keywords

Cite

@article{arxiv.1910.05302,
  title  = {Bijective Cremona transformations of the plane},
  author = {Shamil Asgarli and Kuan-Wen Lai and Masahiro Nakahara and Susanna Zimmermann},
  journal= {arXiv preprint arXiv:1910.05302},
  year   = {2022}
}

Comments

51 pages, removed section 5.A and made improvements on exposition, to appear in Selecta Mathematica

R2 v1 2026-06-23T11:41:19.783Z