Ideal amenability of module extensions of Banach algebras

Eshaghi M. Gordji; F. Habibian; B. Hayati

Displaying similar documents to “Ideal amenability of module extensions of Banach algebras”

A generalized notion of $n$ -weak amenability

Abasalt Bodaghi, Behrouz Shojaee (2014)

Mathematica Bohemica

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In the current work, a new notion of $n$ -weak amenability of Banach algebras using homomorphisms, namely $(ϕ, ψ)$ - $n$ -weak amenability is introduced. Among many other things, some relations between $(ϕ, ψ)$ - $n$ -weak amenability of a Banach algebra $𝒜$ and $M_{m} (𝒜)$ , the Banach algebra of $m \times m$ matrices with entries from $𝒜$ , are studied. Also, the relation of this new concept of amenability of a Banach algebra and its unitization is investigated. As an example, it is shown that the group algebra $L^{1} (G)$ is ( $ϕ, ψ$ )- $n$ -weakly amenable...

Weak amenability of the second dual of a Banach algebra

M. Eshaghi Gordji, M. Filali (2007)

Studia Mathematica

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It is known that a Banach algebra inherits amenability from its second Banach dual **. No example is yet known whether this fails if one considers the weak amenability instead, but the property is known to hold for the group algebra L¹(G), the Fourier algebra A(G) when G is amenable, the Banach algebras which are left ideals in **, the dual Banach algebras, and the Banach algebras which are Arens regular and have every derivation from into * weakly compact. In this paper, we extend this...

Problems concerning $n$ -weak amenability of a Banach algebra

Alireza Medghalchi, Taher Yazdanpanah (2005)

Czechoslovak Mathematical Journal

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In this paper we extend the notion of $n$ -weak amenability of a Banach algebra $𝒜$ when $n \in ℕ$ . Technical calculations show that when $𝒜$ is Arens regular or an ideal in $𝒜^{* *}$ , then $𝒜^{*}$ is an $𝒜^{(2 n)}$ -module and this idea leads to a number of interesting results on Banach algebras. We then extend the concept of $n$ -weak amenability to $n \in ℤ$ .

Some notions of amenability for certain products of Banach algebras

Eghbal Ghaderi, Rasoul Nasr-Isfahani, Mehdi Nemati (2013)

Colloquium Mathematicae

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For two Banach algebras and ℬ, an interesting product $\times_{θ} ℬ$ , called the θ-Lau product, was recently introduced and studied for some nonzero characters θ on ℬ. Here, we characterize some notions of amenability as approximate amenability, essential amenability, n-weak amenability and cyclic amenability between and ℬ and their θ-Lau product.

Constructions preserving $n$ -weak amenability of Banach algebras

A. Jabbari, Mohammad Sal Moslehian, H. R. E. Vishki (2009)

Mathematica Bohemica

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A surjective bounded homomorphism fails to preserve $n$ -weak amenability, in general. We however show that it preserves the property if the involved homomorphism enjoys a right inverse. We examine this fact for certain homomorphisms on several Banach algebras.

Arens regularity of module actions

M. Eshaghi Gordji, M. Filali (2007)

Studia Mathematica

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We study the Arens regularity of module actions of Banach left or right modules over Banach algebras. We prove that if has a brai (blai), then the right (left) module action of on * is Arens regular if and only if is reflexive. We find that Arens regularity is implied by the factorization of * or ** when is a left or a right ideal in **. The Arens regularity and strong irregularity of are related to those of the module actions of on the nth dual $^{(n)}$ of . Banach algebras for which Z( **)...

Approximate amenability for Banach sequence algebras

H. G. Dales, R. J. Loy, Y. Zhang (2006)

Studia Mathematica

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We consider when certain Banach sequence algebras A on the set ℕ are approximately amenable. Some general results are obtained, and we resolve the special cases where $A = ℓ^{p}$ for 1 ≤ p < ∞, showing that these algebras are not approximately amenable. The same result holds for the weighted algebras $ℓ^{p} (ω)$ .

(Non-)amenability of ℬ(E)

Volker Runde (2010)

Banach Center Publications

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In 1972, the late B. E. Johnson introduced the notion of an amenable Banach algebra and asked whether the Banach algebra ℬ(E) of all bounded linear operators on a Banach space E could ever be amenable if dim E = ∞. Somewhat surprisingly, this question was answered positively only very recently as a by-product of the Argyros-Haydon result that solves the “scalar plus compact problem”: there is an infinite-dimensional Banach space E, the dual of which is ℓ¹, such that $ℬ (E) = (E) + ℂ i d_{E}$ . Still, ℬ(ℓ²) is...

Strict u-ideals in Banach spaces

Vegard Lima, Åsvald Lima (2009)

Studia Mathematica

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We study strict u-ideals in Banach spaces. A Banach space X is a strict u-ideal in its bidual when the canonical decomposition $X * * * = X * \oplus X^{⊥}$ is unconditional. We characterize Banach spaces which are strict u-ideals in their bidual and show that if X is a strict u-ideal in a Banach space Y then X contains c₀. We also show that $ℓ_{\infty}$ is not a u-ideal.

The Kadison problem on a class of commutative Banach algebras with closed cone

M. A. Toumi (2010)

Commentationes Mathematicae Universitatis Carolinae

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The main result of the paper characterizes continuous local derivations on a class of commutative Banach algebra $A$ that all of its squares are positive and satisfying the following property: Every continuous bilinear map $Φ$ from $A \times A$ into an arbitrary Banach space $B$ such that $Φ (a, b) = 0$ whenever $a b = 0$ , satisfies the condition $Φ (a b, c) = Φ (a, b c)$ for all $a, b, c \in A$ .