Subgroups in which a Cohomology Class Splits

William A. Stein
January 25, 1999

Let GG be a group, MM a Z[G]\Z[G]-module, and cHq(G,M)c\in H^q(G,M). We study the indexes of subgroups HGH\subset G for which cc restricts to 00. In particular, we investigate the situation when the greatest common divisor of the indexes is itself an index.