Periodicity in the cohomology of symmetric groups via divided powers
Periodicity in the cohomology of symmetric groups via divided powers
A famous theorem of Nakaoka asserts that the cohomology of the symmetric group stabilizes. The first author generalized this theorem to non-trivial coefficient systems, in the form of FI-modules over a field, though one now obtains periodicity of the cohomology instead of stability. In this paper, we further refine these …