Mathematical Research Letters
Volume 14 (2007)
Subgroups of direct products of two limit groups
Pages: 547 – 558
If $\G_1$ and $\G_2$ are limit groups and $S\subset \G_1\times\G_2$ is of type $\FP_2$ then $S$ has a subgroup of finite index that is a product of at most two limit groups.