Hostname: page-component-78c5997874-8bhkd Total loading time: 0 Render date: 2024-11-10T16:01:29.550Z Has data issue: false hasContentIssue false

SERRE'S THEOREM ON THE COHOMOLOGY ALGEBRA OF A p-GROUP

Published online by Cambridge University Press:  01 September 1998

PHAM ANH MINH
Affiliation:
Department of Mathematics, College of Sciences, University of Hue, Dai hoc Khoa hoc, Hue, Vietnam
Get access

Abstract

The purpose of this note is to give a proof of a theorem of Serre, which states that if G is a p-group which is not elementary abelian, then there exist an integer m and non-zero elements x1, … xmH1 (G, Z/p) such that

formula here

with β the Bockstein homomorphism. Denote by mG the smallest integer m satisfying the above property. The theorem was originally proved by Serre [5], without any bound on mG. Later, in [2], Kroll showed that mG[les ]pk−1, with k=dimZ/pH1 (G, Z/p). Serre, in [6], also showed that mG[les ](pk−1)/ (p−1). In [3], using the Evens norm map, Okuyama and Sasaki gave a proof with a slight improvement on Serre's bound; it follows from their proof (see, for example, [1, Theorem 4.7.3]) that mG[les ](p+1) pk−2. However, mG can be sharpened further, as we see below.

For convenience, write H*ast;(G, Z/p)=H*(G). For every xiH1(G), set

formula here

Type
Notes and Papers
Copyright
© The London Mathematical Society 1998

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)