We first develop some basic facts about hypergeometric sheaves on the multiplicative group m in characteristic p > 0. Certain of their Kummer pullbacks extend to irreducible local systems on the affine line in characteristic p > 0. One of these, of rank 23 in characteristic p = 3, turns out to have the Conway group Co2, in its irreducible orthogonal representation of degree 23, as its arithmetic and geometric monodromy groups.
All Science Journal Classification (ASJC) codes
- Algebra and Number Theory
- Rigid local systems
- monodromy groups
- sporadic simple groups