• Honam Mathematical Journal
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• v.43 no.2
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• pp.209-219
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• 2021

We define a new concept of module amenability which is compatible with original definition of amenability. For a module dual algebra 𝓐, we will show that if every module derivation D : 𝓐** → J𝓐**⊥ is inner then 𝓐 is weak module amenable. Moreover, we will prove that under certain conditions, weak module amenability of 𝓐** implies weak module amenability of 𝓐.

• Honam Mathematical Journal
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• v.42 no.3
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• pp.537-550
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• 2020

Let A, B, 𝔘 be Banach algebras and B be a Banach 𝔘-bimodule also A be a Banach B-𝔘-module. In this paper we study the relation between module amenability, weak module amenability and module approximate amenability of module Lau product A × _α B and that of Banach algebras A, B.

• Honam Mathematical Journal
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• v.42 no.1
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• pp.37-48
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• 2020

We first define a new multiplication on triangular Banach algebras. Then we study amenability, weak amenability, biflatness and biprojectivity of these algebras.

• Bulletin of the Korean Mathematical Society
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• v.47 no.2
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• pp.307-317
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• 2010

In this paper we find necessary and sufficient conditions for weak amenability of the convolution Banach algebras A(K) and $L^2(K)$ for a compact hypergroup K, together with their applications to convolution Banach algebras $L^p(K)$ ($2\;{\leq}\;p\;<\;{\infty}$). It will further be shown that the convolution Banach algebra A(G) for a compact group G is weakly amenable if and only if G has a closed abelian subgroup of finite index.

• Bulletin of the Korean Mathematical Society
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• v.54 no.6
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• pp.1991-1999
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• 2017

Let A and B be two Banach algebras and $T:B{\rightarrow}A$ be a bounded homomorphism, with ${\parallel}T{\parallel}{\leq}1$. Recently, Dabhi, Jabbari and Haghnejad Azar (Acta Math. Sin. (Engl. Ser.) 31 (2015), no. 9, 1461-1474) obtained some results about the n-weak amenability of $A{\times}_TB$. In the present paper, we address a gap in the proof of these results and extend and improve them by discussing general necessary and sufficient conditions for $A{\times}_TB$ to be n-weakly amenable, for an integer $n{\geq}0$.

• Bulletin of the Korean Mathematical Society
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• v.42 no.2
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• pp.359-367
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• 2005

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

• Bulletin of the Korean Mathematical Society
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• v.58 no.5
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• pp.1209-1219
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• 2021

Let G be a topological group with a locally compact and Hausdorff topology. Let ω be a diagonally bounded weight on G. In this paper, (σ, σ)-derivation and (σ, 𝜏)-weak amenability of the Beurling algebra L¹_ω(G) are studied, where σ, 𝜏 are isometric automorphisms of L¹_ω(G). We prove that every continuous (σ, σ)-derivation from L¹_ω(G) into measure algebra M_ω(G) is (σ, σ)-inner and the Beurling algebra L¹_ω(G) is (σ, 𝜏)-weakly amenable.

• Bulletin of the Korean Mathematical Society
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• v.47 no.4
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• pp.663-673
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• 2010

This work was intended as an attempt to introduce and investigate the Connes-amenability of module extension of dual Banach algebras. It is natural to try to study the $weak^*$-continuous derivations on the module extension of dual Banach algebras and also the weak Connes-amenability of such Banach algebras.