Page 1 Next

Displaying 1 – 20 of 149

Showing per page

Capacités invariantes extrémales

Michel Talagrand (1978)

Annales de l'institut Fourier

On étudie certains cônes de mesures 0 sur un espace localement compact, qui sont invariantes par l’action continue d’un groupe localement compact G , cette étude étant centrée sur les génératrices extrémales de ces cônes. On dégage d’abord un type très simple d’action continue où l’on décrit complètement la situation. On dégage ensuite une classe d’actions (contenant par exemple l’action de shift de Bernoulli sur { 0 , 1 } N ) qui ne sont pas du type précédent, et que l’on étudie en grand détail. Le résultat...

Central sidonicity for compact Lie groups

Kathryn E. Hare (1995)

Annales de l'institut Fourier

It is known that the dual of a compact, connected, non-abelian group may contain no infinite central Sidon sets, but always does contain infinite central p -Sidon sets for p > 1 . We prove, by an essentially constructive method, that the latter assertion is also true for every infinite subset of the dual. In addition, we investigate the relationship between weighted central Sidonicity for a compact Lie group and Sidonicity for its torus.

Character Connes amenability of dual Banach algebras

Mohammad Ramezanpour (2018)

Czechoslovak Mathematical Journal

We study the notion of character Connes amenability of dual Banach algebras and show that if A is an Arens regular Banach algebra, then A * * is character Connes amenable if and only if A is character amenable, which will resolve positively Runde’s problem for this concept of amenability. We then characterize character Connes amenability of various dual Banach algebras related to locally compact groups. We also investigate character Connes amenability of Lau product and module extension of Banach algebras....

Character contractibility of Banach algebras and homological properties of Banach modules

Rasoul Nasr-Isfahani, Sima Soltani Renani (2011)

Studia Mathematica

Let 𝓐 be a Banach algebra and let ϕ be a nonzero character on 𝓐. We give some necessary and sufficient conditions for the left ϕ-contractibility of 𝓐 as well as several hereditary properties. We also study relations between homological properties of some Banach left 𝓐-modules, the left ϕ-contractibility and the right ϕ-amenability of 𝓐. Finally, we characterize the left character contractibility of various Banach algebras related to locally compact groups.

Character inner amenability of certain Banach algebras

H. R. Ebrahimi Vishki, A. R. Khoddami (2011)

Colloquium Mathematicae

Character inner amenability for a certain class of Banach algebras including projective tensor products, Lau products and module extensions is investigated. Some illuminating examples are given.

Character pseudo-amenability of Banach algebras

Rasoul Nasr-Isfahani, Mehdi Nemati (2013)

Colloquium Mathematicae

Let 𝓐 be a Banach algebra and let ϕ be a nonzero character on 𝓐. We introduce and study a new notion of amenability for 𝓐 based on existence of a ϕ-approximate diagonal by modifying the concepts of ϕ-amenability and pseudo-amenability. We then apply these results to characterize ϕ-pseudo-amenability of various Banach algebras related to locally compact groups such as group algebras, measure algebras, certain dual algebras and Lebesgue-Fourier algebras.

Character sums in complex half-planes

Sergei V. Konyagin, Vsevolod F. Lev (2004)

Journal de Théorie des Nombres de Bordeaux

Let A be a finite subset of an abelian group G and let P be a closed half-plane of the complex plane, containing zero. We show that (unless A possesses a special, explicitly indicated structure) there exists a non-trivial Fourier coefficient of the indicator function of A which belongs to P . In other words, there exists a non-trivial character χ G ^ such that a A χ ( a ) P .

Characterising weakly almost periodic functionals on the measure algebra

Matthew Daws (2011)

Studia Mathematica

Let G be a locally compact group, and consider the weakly almost periodic functionals on M(G), the measure algebra of G, denoted by WAP(M(G)). This is a C*-subalgebra of the commutative C*-algebra M(G)*, and so has character space, say K W A P . In this paper, we investigate properties of K W A P . We present a short proof that K W A P can naturally be turned into a semigroup whose product is separately continuous; at the Banach algebra level, this product is simply the natural one induced by the Arens products. This...

Currently displaying 1 – 20 of 149

Page 1 Next