Restriction to finite-index subgroups as étale extensions in topology, KK–theory and geometry

Abstract

Author(s): Balmer, P; Dell’Ambrogio, I; Sanders, B | Abstract: © 2015, Mathematical Sciences Publishers. All rights reserved. For equivariant stable homotopy theory, equivariant KK–theory and equivariant derived categories, we show how restriction to a subgroup of finite index yields a finite commutative separable extension, analogous to finite etale extensions in algebraic geometry.