Solvability of the conjugacy problem for relatively hyperbolic groups was announced by Gromov [12]. Using the definition of Farb of a relatively hyperbolic group [9], we prove this assertion. We conclude that the conjugacy problem is solvable for the following two classes of groups: fundamental groups of complete, finite-volume, negatively curved manifolds, and finitely generated fully residual...

In his paper ”Finite groups have many conjugacy classes” (J. London Math. Soc (2) 46 (1992), 239-249), L. Pyber proved the to date best general lower bounds for the number of conjugacy classes of a finite group in terms of the order of the group. In this paper we strengthen the main results in Pyber’s paper.

We establish the first super-logarithmic lower bound for the number of conjugacy classes of a finite nilpotent group. In particular, for any constant c there are only finitely many finite p-groups of order pm with at most c ·m conjugacy classes. This answers a question of L. Pyber.

We give a complete classification up to cocycle conjugacy of uniformly outer actions of Z on UHF algebras. In particular, it is shown that any two uniformly outer actions of Z on a UHF algebra of infinite type are cocycle conjugate. We also classify them up to outer conjugacy.

There are recent cryptographic protocols that are based on Multiple Simultaneous Conjugacy Problems in braid groups. We improve an algorithm, due to Sang Jin Lee and Eonkyung Lee, to solve these problems, by applying a method developed by the author and Nuno Franco, originally intended to solve the Conjugacy Search Problem in braid groups.

In this note, we give characterizations for certain HNN extensions of polycyclic-by-finite groups with central associated subgroups to be subgroup separable and conjugacy separable. We shall do this by showing the equivalence of subgroup separability and conjugacy separability in this type of HNN extensions. 2000 Mathematics Subject Classification: Primary 20E06, 20E26; Secondary 20F10, 20F19

We describe the relation between two characterizations of conjugacy in groups of piecewise-linear homeomorphisms, discovered by Brin and Squier in [2] and Kassabov and Matucci in [5]. Thanks to the interplay between the techniques, we produce a simplified point of view of conjugacy that allows ua to easily recover centralizers and lends itself to generalization.

We construct a hyperbolic group containing a finitely presented subgroup, which has infinitely many conjugacy classes of finite-order elements. We also use a version of Morse theory with high dimensional horizontal cells and use handle cancellation arguments to produce other examples of subgroups of CAT(0) groups with infinitely many conjugacy classes of finite-order elements.

In this paper we classify all finite solvable groups satisfying the following property P5: their orders of representatives are set-wise relatively prime for any 5 distinct non-central conjugacy classes.

For a finite group $G$ let $nu(G)$ denote the number of conjugacy classes of non-normal subgroups of $G$. We give a short proof of a theorem of Brandl, which classifies finite groups with $nu(G)=1$.