Actions of a noncompact semigroup with zero.
Actions of discrete groups on nonpositively curved spaces.
Actions of finite groups on C*-algebras.
Actions of finitely generated groups on -trees
We study actions of finitely generated groups on -trees under some stability hypotheses. We prove that either the group splits over some controlled subgroup (fixing an arc in particular), or the action can be obtained by gluing together actions of simple types: actions on simplicial trees, actions on lines, and actions coming from measured foliations on -orbifolds. This extends results by Sela and Rips-Sela. However, their results are misstated, and we give a counterexample to their statements.The...
Actions of groups on lattices.
Actions of monoidally equivalent compact quantum groups and applications to probabilistic boundaries
The notion of monoidal equivalence for compact quantum groups was recently introduced by Bichon, De Rijdt and Vaes. In this paper we prove that there is a natural bijective correspondence between actions of monoidally equivalent quantum groups on unital -algebras or on von Neumann algebras. This correspondence turns out to be very useful to obtain the behavior of Poisson and Martin boundaries under monoidal equivalence of quantum groups. Finally, we apply these results to identify the Poisson boundary...
Actions of semilattices.
Active sums I.
Given a generating family F of subgroups of a group G closed under conjugation and with partial order compatible with inclusion, a new group S can be constructed, taking into account the multiplication in the subgroups and their mutual actions given by conjugation. The group S is called the active sum of F, has G as a homomorph and is such that S/Z(S) ≅ G/Z(G) where Z denotes the center.The basic question we investigate in this paper is: when is the active sum S of the family F isomorphic to the...
Active sums of groups.
Acyclic groups of automorphisms.
Addendum and corrigendum to «Automorfismi che fissano i centralizzanti di un gruppo»
Addendum : Finiteness theorems for discrete subgroups of bounded covolume in semi-simple groups
Addendum to "A survey of semigroups of continuous selfmaps" (with intro. by K. D. Magill).
Addendum to : “Prime graph components of finite almost simple groups” [Rend. Sem. Mat. Univ. Padova 102 (1999), 1–22]
Addendum to: Representations of inverse semigroups by one-to-one partial transformations of a set.
Addition and correction to the paper "Diagonal algebras"
Addition molle et fonctions p-locales.
Addition of rational fuzzy quantities: Convolutive approach
Additional notes on continuity in semitopological semigroups.
Adèles et groupes algébriques