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Amenability of any of the algebras described in the title is known to force them to be finite-dimensional. The analogous problems for \emph{approximate} amenability have been open for some years now. In this article we give a complete…

Functional Analysis · Mathematics 2011-04-11 Yemon Choi , Fereidoun Ghahramani

In this paper, we introduce and study some notations of amenability such as $n$-ideal amenability and $n$-weak amenability for Frechet algebra and we examine how these concepts in Banach algebra can be generalized and defined for Frechet…

Functional Analysis · Mathematics 2021-11-30 Ali Rejali , Ali Ranjbari

We develop a theory of large scale geometry of metrisable topological groups that, in a significant number of cases, allows one to define and identify a unique quasi-isometry type intrinsic to the topological group. Moreover, this…

Group Theory · Mathematics 2014-03-14 Christian Rosendal

We show that every metric space with bounded geometry uniformly embeds into an explicit reflexive Banach space (a direct sum of l^p spaces). In the case of discrete groups we show the analogue of a-T-menability. That is, we construct a…

Operator Algebras · Mathematics 2016-09-07 Nathanial Brown , Erik Guentner

We show that if $T$ is an isometry (as metric spaces) between the invertible groups of unital Banach algebras, then $T$ is extended to a surjective real-linear isometry up to translation between the two Banach algebras. Furthermore if the…

Functional Analysis · Mathematics 2009-04-21 Osamu Hatori

We give a survey of our recent results on homological properties of K"othe algebras, with an emphasis on biprojectivity, biflatness, and homological dimension. Some new results on the approximate contractibility of K"othe algebras are also…

Functional Analysis · Mathematics 2010-06-29 A. Yu. Pirkovskii

We shall develop a notion of amenability for dual Banach algebras, namely weak Connes amenability, which will play the role that weak amenability does for usual Banach algebras

Functional Analysis · Mathematics 2021-09-02 Amin Mahmoodi

Motivated by the classical correspondence between short exact sequences and splitting properties in module theory, this paper examines the projective and injective analogues within the category of Lie algebras. We first show that no Lie…

Rings and Algebras · Mathematics 2025-11-18 Vu A. Le , Hoa Q. Duong , Tuan A. Nguyen

In this paper we study injective modules over universal enveloping algebras of finite-dimensional Lie algebras over fields of arbitrary characteristic. Most of our results are dealing with fields of prime characteristic but we also…

Representation Theory · Mathematics 2007-05-23 Joerg Feldvoss

In this paper, we give another two characterizations of relative amenability on finite von Neumann algebras, one of which can be thought of as an analogue of injective operator systems. As an application, we prove a stable property of…

Operator Algebras · Mathematics 2018-07-06 Xiaoyan Zhou , Junsheng Fang

We introduce two notions of amenability for a Banach algebra $\cal A$. Let $n\in \Bbb N$ and let $I$ be a closed two-sided ideal in $\cal A$, $\cal A$ is $n-I-$weakly amenable if the first cohomology group of $\cal A$ with coefficients in…

Functional Analysis · Mathematics 2007-05-23 M. Eshaghi Gordji , R. Memarbashi

In this paper, we study the weak amenability of weighted measure algebras and prove that $M(G, \omega)$ is weakly amenable if and only if $G$ is discrete and every bounded quasi-additive function is inner. We also study the weak amenability…

Functional Analysis · Mathematics 2022-10-11 M. J. Mehdipour , A. Rejali

In this paper we will study the homological properties of various natural modules associated to the Fourier algebra of a locally compact group. In particular, we will focus on the question of identifying when such modules will be projective…

Functional Analysis · Mathematics 2014-02-26 Brian E. Forrest , Hun Hee Lee , Ebrahim Samei

Building on our previous work, we study the non-relative homology of quantum group convolution algebras. Our main result establishes the equivalence of amenability of a locally compact quantum group $\mathbb{G}$ and 1-injectivity of…

Operator Algebras · Mathematics 2016-03-16 Jason Crann

In this paper, we investigate homological properties of Banach algebras. We show that retractions Banach algebras preserve biprojectivity, contractibility and biflatness. We also prove that contractibility of second dual of a Banach algebra…

Functional Analysis · Mathematics 2022-11-01 M. J. Mehdipour , A. Rejali

For two Banach algebras $A$ and $B$, the $T$-Lau product $A\times_T B$, was recently introduced and studied for some bounded homomorphism $T:B\to A$ with $\|T\|\leq 1$. Here, we give general nessesary and sufficent conditions for $A\times_T…

Functional Analysis · Mathematics 2017-01-24 Mohammad Ramezanpour

In this paper, we investigate the notion of approximate biprojectivity for semigroup algebras and for some Banach algebras related to semigroup algebras. We show that $\ell^{1}(S)$ is approximately biprojective if and only if $\ell^{1}(S)$…

Functional Analysis · Mathematics 2014-09-29 A. Sahami , A. Pourabbas

In this paper, we study the notion of approximately bi at Banach algebras for second dual Banach algebras and semigroup algebras. We show that for a locally compact group G, if S(G)?? is approximately bi at, then G is amenable group. Also…

Functional Analysis · Mathematics 2016-10-04 Amir Sahami

For a Banach algebra A and a closed ideal I, the notion of bounded approximate diagonal modulo I has been studied and investigated. In this paper we define the notion of locally bounded approximate diagonal modulo an ideal I for a Frechet…

Functional Analysis · Mathematics 2019-01-11 Somayeh Rahnama , Ali Rejali

In this paper, we deal with cohomological properties of weak amenability, cyclic amenability, cyclic weak amenability and point amenability of Banach algebras. We look at some hereditary properties of them and show that continuous…

Functional Analysis · Mathematics 2022-10-10 M. J. Mehdipour , A. Rejali