Abhyankar's Inertia Conjecture for Some Sporadic Groups

Abstract

This paper verifies Abhyankar's Inertia Conjecture for certain sporadic groups $G$ in particular characteristics by showing that all possible inertia groups occur for $G$-Galois covers of the affine line. For a larger set of sporadic groups, all but finitely many possible ramification invariants are shown to occur. In particular, we prove that all but eight of the possible ramification invariants are realizable for ${\text{M}}_{11}$-Galois covers of the affine line.

18 pages