Bulletin of the
Korean Mathematical Society
BKMS

ISSN(Print) 1015-8634 ISSN(Online) 2234-3016

Article

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Bull. Korean Math. Soc. 2005; 42(2): 359-367

Printed June 1, 2005

Copyright © The Korean Mathematical Society.

$n$-weak amenability and strong double limit property

A.R. Medghalchi and T. Yazdanpanah

Teacher Training University, Persian Gulf University

Abstract

Let ${\mathcal A}$ be a Banach algebra, we say that ${\mathcal A}$ has the strongly double limit property (SDLP) if for each bounded net $(a_{\alpha})$ in ${\mathcal A}$ and each bounded net $(a^*_{\beta})$ in ${\mathcal A}^*$, $\lim_{\alpha}\lim_{\beta} \left\langle a_{\alpha} , a^*_{\beta}\right\rangle = \lim_{\beta} \lim_{\alpha} \left\langle a_{\alpha} , a^*_{\beta} \right\rangle $ whenever both iterated limits exist. In this paper among other results we show that if ${\mathcal A}$ has the SDLP and ${\mathcal A}^{**}$ is $(n-2)$-weakly amenable, then ${\mathcal A}$ is $n$-weakly amenable. In particular, it is shown that if ${\mathcal A}^{**}$ is weakly amenable and ${\mathcal A}$ has the SDLP, then ${\mathcal A}$ is weakly amenable.

Keywords: Banach algebra, weak amenability, Arens regular, $n$-weak amenability

MSC numbers: 46H20, 46H40