Displaying similar documents to “Platonic triangles of groups.”

Conjugacy pinched and cyclically pinched one-relator groups.

Benjamin Fine, Gerhard Rosenberger, Michael Stille (1997)

Revista Matemática de la Universidad Complutense de Madrid

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Here we consider two classes of torsion-free one-relator groups which have proved quite amenable to study-the cyclically pinched one-relator groups and the conjugacy pinched one-relator groups. The former is the class of groups which are free products of free groups with cyclic amalgamations while the latter is the class of HNN extensions of free groups with cyclic associated subgroups. Both are generalizations of surface groups. We compare and contrast results in these classes relative...

Butler groups splitting over a base element

Clorinda De Vivo, Claudia Metelli (2007)

Colloquium Mathematicae

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We characterize a particular kind of decomposition of a Butler group that is the general case for Butler B(1)-groups; and exhibit a decomposition of a B(2)-group which is not of that kind.

The nonseparability of simply presented mixed groups

Paul Hill, Charles K. Megibben (1998)

Commentationes Mathematicae Universitatis Carolinae

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It is demonstrated that an isotype subgroup of a simply presented abelian group can be simply presented without being a separable subgroup. In particular, the conjecture based on a variety of special cases that Warfield groups are absolutely separable is disproved.