Title: The essential ideal is a Cohen-Macaulay module
Author: David J. Green, University of Wuppertal, Germany
Date: 26 February 2004
Status: Submitted for publication
MSC 2000: Primary 20J06; Secondary 13C14

Abstract:
Let G be a finite p-group which does not contain a rank two elementary
abelian p-group as a direct factor. Then the ideal of essential classes
in the mod-p cohomology ring of G is a Cohen--Macaulay module whose
Krull dimension is the p-rank of the centre of G.  This basically
answers in the affirmative a question posed by J. F. Carlson.