English

Approximate semi-amenability of Banach algebras

Functional Analysis 2019-10-22 v2

Abstract

Let A\mathfrak{A} be a Banach algebra, and X\mathcal{X} a Banach A\mathfrak{A}-bimodule. A bounded linear mapping D:AX\mathcal{D}:\mathfrak{A}\rightarrow \mathcal{X} is approximately semi-inner derivation if there eixist nets (ξα)α(\xi_{\alpha})_{\alpha} and (μα)α(\mu_{\alpha})_{\alpha} in X\mathcal{X} such that, for each aAa\in\mathfrak{A}, D(a)=limα(a.ξαμα.a)\mathcal{D}(a)=\lim_{\alpha}(a.\xi_{\alpha}-\mu_{\alpha}.a). A\mathfrak{A} is called approximately semi-amenable if for every Banach A\mathfrak{A}-bimodule X\mathcal{X}, every DZ1(A,X)\mathcal{D}\in\mathcal{Z}^{1}(\mathfrak{A},\mathcal{X}^{*}) is approximtely semi-inner. There are some Banach algebras which are approximately semi-amenable, but not approximately amenable. In this manuscript, we investigate some properties of approximate semi-amenability of Banach algebras. Also in Theorem \ref{ee} we prove the approximate semi-amenability of Segal algebras on a locally compact group GG.

Keywords

Cite

@article{arxiv.1909.04874,
  title  = {Approximate semi-amenability of Banach algebras},
  author = {M. Shams Kojanaghi and K. Haghnejad Azar and M. R. Mardanbeigi},
  journal= {arXiv preprint arXiv:1909.04874},
  year   = {2019}
}