Displaying similar documents to “Embedding C(X) in an algebra of analytic functions”

Additively spectral-radius preserving surjections between unital semisimple commutative Banach algebras

Osamu Hatori, Go Hirasawa, Takeshi Miura (2010)

Open Mathematics

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Let A and B be unital, semisimple commutative Banach algebras with the maximal ideal spaces M A and M B, respectively, and let r(a) be the spectral radius of a. We show that if T: A → B is a surjective mapping, not assumed to be linear, satisfying r(T(a) + T(b)) = r(a + b) for all a; b ∈ A, then there exist a homeomorphism φ: M B → M A and a closed and open subset K of M B such that T a ^ y = T e ^ y a ^ φ y y ∈ K T e ^ y a ^ φ y ¯ y ∈ M ℬ ∖ K for all a ∈ A, where e is unit element of A. If, in addition, T e ^ = 1 and T i e ^ = i on M B, then T is an algebra isomorphism. ...

Homomorphisms on some function algebras.

M.ª Isabel Garrido, Javier Gómez Gil, Jesús Angel Jaramillo (1992)

Extracta Mathematicae

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Suppose that A is an algebra of continuous real functions defined on a topological space X. We shall be concerned here with the problem as to whether every nonzero algebra homomorphism φ: A → R is given by evaluation at some point of X, in the sense that there exists some a in X such that φ(f) = f(a) for every f in A. The problem goes back to the work of Michael [19], motivated by the question of automatic continuity of homomorphisms in a symmetric *-algebra. More recently, the problem...