Topological Algebra and its Applications (Jan 2014)
On Gelfand-Mazur theorem on a class of F-algebras
Abstract
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 Gelfand-Mazur theoremfor a large class of F-algebras, containing both locally bounded algebras and locally convex algebras withbounded elements.
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