This article is concerned with conjugacy problems arising in homeomorphisms group, Hom(F ), of non-compact subsets F of normed vector spaces E. Given two homeomorphisms f and g in Hom(F ), it is shown how the existence of a conjugacy may be related to the existence of a common generalized eigenfunction of the associated Koopman operators. This common eigenfunction serves to build a topology on ...

We show that for every effective left conjugacy closed left quasigroup, there is an induced rack that retains the conjugation structure of the left translations. This means that cryptographic protocols relying on conjugacy search can be secure only if conjugacy search of left translations is infeasible in the induced rack. We note that, in fact, protocols based on conjugacy search could be simp...

Topological separability is crucial for the utility representation of a complete preference relation. When preferences are incomplete, this axiom has suitably de…ned counterparts: upper separability and lower separability (Ok (2002)). We consider the problem of representing an incomplete preference relation by means of a vector-valued utility function; we obtain representation results under the...

This article introduces a “pseudo classical” notion of modelling non-separability. This form of non-separability can be viewed as lying between separability and quantum-like non-separability. Non-separability is formalized in terms of the non-factorizabilty of the underlying joint probability distribution. A decision criterium for determining the non-factorizability of the joint distribution is...

Let G be a quasi-split connected reductive group over a local field of characteristic 0, and fix a regular nilpotent element in the Lie algebra g of G. A theorem of Kostant then provides a canonical conjugacy class within each stable conjugacy class of regular semisimple elements in g. Normalized transfer factors take the value 1 on these canonical conjugacy classes.

We classify the real and strongly real conjugacy classes in PGLnðqÞ, PSLnðqÞ, and all quasi-simple covers of PSLnðqÞ. In each case we give a formula for the number of real, and the number of strongly real, conjugacy classes. This is a companion paper to [4] in which we classified the real and strongly real conjugacy classes in GLnðqÞ and SLnðqÞ.

For every finitely generated recursively presented group G we construct a finitely presented group H containing G such that G is (Frattini) embedded into H and the group H has solvable conjugacy problem if and only if G has solvable conjugacy problem. Moreover, G and H have the same r.e. Turing degrees of the conjugacy problem. This solves a problem by D.

We classify the real and strongly real conjugacy classes in PGLnðqÞ, PSLnðqÞ, and all quasi-simple covers of PSLnðqÞ. In each case we give a formula for the number of real, and the number of strongly real, conjugacy classes. This is a companion paper to [4] in which we classified the real and strongly real conjugacy classes in GLnðqÞ and SLnðqÞ.

A conjugacy class C of a finite group G is a sign conjugacy class if every irreducible character of G takes value 0, 1 or −1 on C. In this paper we classify the sign conjugacy classes of the symmetric groups and thereby verify a conjecture of Olsson.