Hypergeometric sheaves and extraspecial groups in even characteristic

TL;DR

This paper classifies certain hypergeometric sheaves with specific symmetry properties in characteristic 2, completing the understanding of their local monodromy at zero for finite geometric monodromy groups.

Contribution

It precisely identifies hypergeometric sheaves with extraspecial normalizers in characteristic 2, resolving a key open case in their monodromy classification.

Findings

Identifies hypergeometric sheaves with extraspecial normalizers in characteristic 2

Completes the classification of local monodromy at 0 for these sheaves

Advances understanding of geometric monodromy groups in algebraic geometry

Abstract

We determine precisely which irreducible hypergeometric sheaves have an extraspecial normalizer in characteristic 2 as their geometric monodromy groups. This resolves the last open case of the determination of local monodromy at 0 of irreducible hypergeometric sheaves with finite geometric monodromy group.