English

Automatic continuity of Some linear mappings from certain products of Banach algebras

Functional Analysis 2019-02-27 v1

Abstract

Let A\mathcal{A} and U\mathcal{U} be Banach algebras and θ\theta be a nonzero character on A\mathcal{A}. Then the \textit{Lau product Banach algebra} A×θU\mathcal{A}\times_{\theta}\mathcal{U} associated with the Banach algebras A\mathcal{A} and U\mathcal{U} is the l1l^1-direct sum AU\mathcal{A}\oplus\mathcal{U} equipped with the algebra multiplication (a,u)(a,u)=(ab,θ(a)u+θ(a)u+uu)(a,aA,u,uU)(a,u)(a',u')=(ab,\theta(a)u'+\theta(a')u+uu')\, (a,a'\in\mathcal{A},u,u'\in\mathcal{U}) and l1l^1-norm. In this paper we shall investigate the derivations and multipliers from this Banach algebras and study the automatic continuity of these mappings. We also study continuity of the derivations for some special cases of Banach algebra U\mathcal{U} and Banach A×θU\mathcal{A}\times_{\theta}\mathcal{U}-bimodule X\mathcal{X} and establish various results on the continuity of derivations and give some examples.

Keywords

Cite

@article{arxiv.1902.10081,
  title  = {Automatic continuity of Some linear mappings from certain products of Banach algebras},
  author = {Hamid Farhadi and Eghbal Ghaderi and Hoger Ghahramani},
  journal= {arXiv preprint arXiv:1902.10081},
  year   = {2019}
}