Free products with amalgamation of finite groups and finite outer automorphism groups of free groups
Frobenius Subgroups of Free Products of Prosolvable Groups.
-тождества и -многообразия
Generators of Free Product with Amalgamation of two Infinite Cyclic Groups.
Geometry of Free Products.
Gleichungen in freien Produkten mit Amalgam.
Group Extensions with Infinite Conjugacy Classes
We characterize the group property of being with infinite conjugacy classes (or icc, i.e. infinite and of which all conjugacy classes except are infinite) for groups which are extensions of groups. We prove a general result for extensions of groups, then deduce characterizations in semi-direct products, wreath products, finite extensions, among others examples we also deduce a characterization for amalgamated products and HNN extensions. The icc property is correlated to the Theory of von Neumann...
Groups of finite quasi-projective dimension.
Growth tightness of free and amalgamated products
Independent generators for congruence subgroups of Hecke groups.
Inverse semigroup varieties with the amalgamation property.
Kartesisch und residuell abgeschlossene Gruppenklassen [Book]
Lengths In Semi-Free Groups.
L'image d'un groupe dans un groupe hyperbolique.
Limit groups and groups acting freely on -trees.
Locally Compact Groups Acting on Trees and Property T.
Mapping tori of free group automorphisms are coherent.
Margulis Lemma, entropy and free products
We prove a Margulis’ Lemma à la Besson-Courtois-Gallot, for manifolds whose fundamental group is a nontrivial free product , without 2-torsion. Moreover, if is torsion-free we give a lower bound for the homotopy systole in terms of upper bounds on the diameter and the volume-entropy. We also provide examples and counterexamples showing the optimality of our assumption. Finally we give two applications of this result: a finiteness theorem and a volume estimate for reducible manifolds.
Mayer-Vietoriss Sequences for HNN-Groups and Homological Duality.
Monoid presentations of groups by finite special string-rewriting systems
We show that the class of groups which have monoid presentations by means of finite special -confluent string-rewriting systems strictly contains the class of plain groups (the groups which are free products of a finitely generated free group and finitely many finite groups), and that any group which has an infinite cyclic central subgroup can be presented by such a string-rewriting system if and only if it is the direct product of an infinite cyclic group and a finite cyclic group.