The Ekedahl Invariants for finite groups

Ivan Martino

Published 2013-12-02, updated 2014-11-18Version 4

In 2009 Ekedahl introduced certain cohomological invariants of finite groups which are naturally related to the invariant theory of groups and to the Noether Problem. We show that these invariants are trivial for every finite group in GL_3(C) and for the fifth discrete Heisenberg group H_5. Moreover in the case of finite groups with abelian projective reduction, this invariants fulfill a recurrence relation in a certain Grothendieck group for abelian groups.