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 apply Voronoi’s algorithm to compute representatives of the conjugacy classes of maximal finite subgroups of the unit group of a maximal order in some simple Q -algebra. This may be used to show in small cases that non-conjugate orders have non-isomorphic unit groups.

The algebraic classification of Cardy for boundary states on a G/H coset CFT of a compact group G, is geometrically realized on the corresponding manifold resulting from gauging the WZW model. The branes consist of H orbits of quantized G conjugacy classes shifted by quantized H conjugacy classes.

We classify the real and strongly real conjugacy classes in GLn(q), SLn(q), PGLn(q), PSLn(q), and all quasi-simple covers of PSLn(q). In each case we give a formula for the number of real, and the number of strongly real, conjugacy classes.

The action of any group on itself by conjugation and the corresponding conjugacy relation play an important role in group theory. There have been several attempts to extend the notion of conjugacy to semigroups. In this paper, we present a new definition of conjugacy that can be applied to an arbitrary semigroup and it does not reduce to the universal relation in semigroups with a zero. We comp...

In analogy to the disjoint cycle decomposition in permutation groups, Ore and Specht define a of elements full monomial group exploit this describe conjugacy classes centralisers group. We generalise their results wreath products whose base need not be finite top acts faithfully on set. parameterise such explicitly. For products, our approach yields efficient algorithms for finding conjugating ...

For a finite group G we define the graph Γ(G) to be the graph whose vertices are the conjugacy classes of cyclic subgroups of G and two conjugacy classes A, B are joined by an edge if for some A ∈ A, B ∈ B A and B permute. We characterise those groups G for which