Chromatic characteristic classes in ordinary group cohomology, by David J. Green, John R. Hunton, and Bjoern Schuster

We study a family of subrings, indexed by the natural numbers, of the mod-p cohomology of a finite group G. hese subrings are based on a family of vn-periodic complex oriented cohomology theories and are constructed as rings of generalised characteristic classes. We identify the varieties associated to these subrings in terms of colimits over categories of elementary abelian subgroups of G, naturally interpolating between the work of Quillen on var(H*(BG)), the variety of the whole cohomology ring, and that of Green and Leary on the variety of the Chern subring, var(Ch(G)). Our subrings give rise to a "chromatic" (co)filtration, which has both topological and algebraic definitions, of var(H*(BG)) whose final quotient is the variety var(Ch(G)).


David J. Green <green@math.uni-wuppertal.de>
John R. Hunton <J.Hunton@mcs.le.ac.uk>
Bjoern Schuster <schuster@math.uni-wuppertal.de>