Quasi-elliptic cohomology of 4-spheres

Abstract

Quasi-elliptic cohomology is conjectured by Sati and Schreiber as a particularly suitable approximation to equivariant 4-th Cohomotopy, which classifies the charges carried by M-branes in M-theory in a way that is analogous to the traditional idea that complex K-theory classifies the charges of D-branes in string theory. In this paper we compute quasi-elliptic cohomology of 4-spheres under the action by some finite subgroups that are the most interesting isotropy groups where the M5-branes may sit.