Let A be a Banach algebra. Then A the second dual of A is a Banach algebra with first (second) Arens product. We study the Arens products of A(= (A∗∗)∗∗). We fined some conditions on A to be a left ideal in A. We fined the biggest two sided ideal I of A, in which I is a left (right) ideal of A∗∗.

Let I be any index set. We consider the Banach algebra Ce + l(I) with the Hadamard product, and prove that its Bass and topological stable ranks are both equal to 1. We also characterize divisors, maximal ideals, closed ideals and closed principal ideals. For I = N we also characterize all prime z-ideals in this Banach algebra.

We prove that a homogeneous Banach space B on the unit circle T can be embedded as a closed subspace of a dual space ΞB contained in the space of bounded Borel measures on T in such a way that the map B → ΞB defines a bijective correspondence between the class of homogeneous Banach spaces on T and the class of prehomogeneous Banach spaces on T. We apply our results to show that the algebra of a...

We give some properties of the Banach algebra of bounded operators (lp(α)) for 1≤ p≤∞, where lp(α)= (1/α)−1∗lp . Then we deal with the continued fractions and give some properties of the operator ∆h for h > 0 or integer greater than or equal to one mapping lp(α) into itself for p ≥ 1 real. These results extend, among other things, those concerning the Banach algebra Sα and some results on the c...

A crossed product is the functional analysts’ version of a skew group ring. Thus, if α : G→ Aut(A) is an action of a locally compact group G on a Banach algebra A, then a crossed product Banach algebra encodes the action of G on A, and its representation theory is related to pairs (u, π) consisting of a representation u of G and a representation π of A on the same Banach space such that ugπ(a)u...

These notes are for a series of lectures given in functional analysis during Winter term of 2015. The two influences of the presentation here are Banach Algebra Techniques in Operator Theory (2e) by Ronald G. Douglas and Lecture Notes on the Spectral Theorem by Dana P. Williams. The notes start with a presentation of the two facts about nets that are required for the subject matter at hand. We ...

We study the lattice of closed (order and algebra) ideals $\mathcal L^r(X)$ when $X$ is a Banach form $(\bigoplus _i \ell _p^i)_q$ $(p\in [1,\infty ]$, $q\in )\cup \{0\} \,\&\, p\ne q)$. show that for every such $X$, $\

In the present paper, the concepts of module (uniform) approximate amenability and contractibility of Banach algebras that are modules over another Banach algebra, are introduced. The general theory is developed and some hereditary properties are given. In analogy with the Banach algebraic approximate amenability, it is shown that module approximate amenability and contractibility are the same ...

Let X,Y be locally compact Hausdorff spaces and M,N be Banach algebras. Let θ : C0(X,M) → C0(Y,N ) be a zero-product preserving bounded linear map with dense range. We show that θ is given by a continuous field of algebra homomorphisms from M into N if N is irreducible. As corollaries, such a surjective θ arises from an algebra homomorphism, provided thatM is a W*-algebra and N is a semi-simple...

For locally compact groups, Fourier algebras and Fourier-Stieltjes algebras have proved to be useful dual objects. They encode the representation theory of the group via the positive deenite functions on the group: positive deenite functions correspond to cyclic representations and span these algebras as linear spaces. They encode information about the algebra of the group in the geometry of th...