Finitely Presented Subgroups of a Product of Two Free Groups
نویسندگان
چکیده
We use van Kampen diagram techniques to give a new geometric proof of Baumslag and Roseblade’s result that a non–free finitely presented subgroup of a direct product of two free groups is virtually a product of subgroups of the factors.
منابع مشابه
2 3 Ju n 20 05 Subgroups of direct products of elementarily free groups
We exploit Zlil Sela’s description of the structure of groups having the same elementary theory as free groups: they and their finitely generated subgroups form a prescribed subclass E of the hyperbolic limit groups. We prove that if G1, . . . , Gn are in E then a subgroup Γ ⊂ G1 × · · · × Gn is of type FPn if and only if Γ is itself, up to finite index, the direct product of at most n groups f...
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