English

The inverse Galois problem for connected algebraic groups

Algebraic Geometry 2024-06-26 v2

Abstract

We show that each connected group scheme of finite type over an arbitrary ground field is isomorphic to the component of the identity inside the automorphism group scheme of some projective, geometrically integral scheme. The main ingredients are embeddings into smooth group schemes, equivariant completions, blow-ups of orbit closures, Fitting ideals for K\"ahler differentials, and Blanchard's Lemma.

Keywords

Cite

@article{arxiv.2205.08117,
  title  = {The inverse Galois problem for connected algebraic groups},
  author = {Michel Brion and Stefan Schröer},
  journal= {arXiv preprint arXiv:2205.08117},
  year   = {2024}
}

Comments

Minor changes. Final version, to appear in Transformation Groups

R2 v1 2026-06-24T11:19:27.428Z