Invariant means and semigroups of nonexpansive mappings on uniformly convex Banach spaces (Q1173887)

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scientific article; zbMATH DE number 7675
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Invariant means and semigroups of nonexpansive mappings on uniformly convex Banach spaces
scientific article; zbMATH DE number 7675

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    Invariant means and semigroups of nonexpansive mappings on uniformly convex Banach spaces (English)
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    25 June 1992
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    Let \(S\) be a semitopological semigroup. Let \({RUC}(S)\) denote the space of all bounded rightly continuous real valued function on \(S\). For this space, the author proves the following theorem. Theorem: Let \(S\) be a semitopological semigroup. Let \({\mathcal S}=\{T_ s;\;s\in S\}\) be a continuous representation of \(S\) as nonexpansive mappings on a closed convex subset \(C\) of a uniformly convex and uniformly smooth Banach space \(E\) into \(C\). If \({RUC}(S)\) has a left invariant mean, and \(C\) contains an element \(x\) with bounded orbit, then there exists \(u\in C\) such that \(T_ s u=u\) for all \(s\in S\).
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    semitopological semigroup
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    nonexpansive mappings on a closed convex subset
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    uniformly convex and uniformly smooth Banach space
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    left invariant mean
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