## A Mayer-Vietoris sequence in group homology and the decomposition of relation modules

### A.J. Duncan, Graham J. Ellis and N.D. Gilbert

#### Status

*Glasgow Math. J.*, ** 37**
(1995), no. 2, 159--171. ** ISSN 0017--0895**

#### Abstract

We obtain an eleven-term exact sequence in the low-dimensional homology of groups by means of mapping
cone constructions on classifying spaces. Properties of the sequence
are related to the notion of independence of normal subgroups
and are used to deduce decomposition of relation
modules for presentations with independent relation subgroups.
Detailed consideration is given to independence of relation subgroups in
presentations of one-relator products.

You can request a copy by
e-mailing me.

*Andrew Duncan*

19 May 1999.