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On character amenable Banach algebras

Z. Hu, M. Sangani Monfared, T. Traynor (2009)

Studia Mathematica

We obtain characterizations of left character amenable Banach algebras in terms of the existence of left ϕ-approximate diagonals and left ϕ-virtual diagonals. We introduce the left character amenability constant and find this constant for some Banach algebras. For all locally compact groups G, we show that the Fourier-Stieltjes algebra B(G) is C-character amenable with C < 2 if and only if G is compact. We prove that if A is a character amenable, reflexive, commutative Banach algebra, then A...

On (Co)homology of triangular Banach algebras

Mohammad Sal Moslehian (2005)

Banach Center Publications

Suppose that A and B are unital Banach algebras with units 1 A and 1 B , respectively, M is a unital Banach A,B-module, = A M 0 B is the triangular Banach algebra, X is a unital -bimodule, X A A = 1 A X 1 A , X B B = 1 B X 1 B , X A B = 1 A X 1 B and X B A = 1 B X 1 A . Applying two nice long exact sequences related to A, B, , X, X A A , X B B , X A B and X B A we establish some results on (co)homology of triangular Banach algebras.

On derivations and crossed homomorphisms

Viktor Losert (2010)

Banach Center Publications

We discuss some results about derivations and crossed homomorphisms arising in the context of locally compact groups and their group algebras, in particular, L¹(G), the von Neumann algebra VN(G) and actions of G on related algebras. We answer a question of Dales, Ghahramani, Grønbæk, showing that L¹(G) is always permanently weakly amenable. Then we show that for some classes of groups (e.g. IN-groups) the homology of L¹(G) with coefficients in VN(G) is trivial. But this is no longer true, in general,...

On Gelfand-Mazur theorem on a class of F -algebras

E. Anjidani (2014)

Topological Algebra and its Applications

A topological algebra A is said to be fundamental if there exists b > 1 such that for every sequence (xn) in A, (xn) is Cauchy whenever the sequence bn(xn − xn-1) tends to zero as n → ∞. Let A be a complex unital fundamental F-algebra with bounded elements such that A* separates the points on A. Then we prove that the spectrum σ(a) of every element a ∈ A is nonempty compact. Moreover, if A is a division algebra, then A is isomorphic to the complex numbers ℂ. This result is a generalization of...

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