2022/07/17 by Michel Brion, Brion, Michel
Mathematics · #14H37 #14J50 (Secondary) #14L15 #14L30 (Primary) 14E07 #Advanced Algebra and Geometry #Algebraic Geometry (math.AG) #Algebraic Geometry and Number Theory #FOS: Mathematics #Homotopy and Cohomology in Algebraic Topology
paper · pdf · doi:10.48550/arxiv.2207.08209
openalex publication_date 2022/07/17 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Every action of a finite group scheme G on a variety admits a projective equivariant model, but not necessarily a normal one. As a remedy, we introduce and explore the notion of G-normalization. In particular, every curve equipped with a G-action has a unique projective G-normal model, characterized by the invertibility of ideal sheaves of all orbits. Also, G-normal curves occur naturally in some questions on surfaces in positive characteristics.