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A characterization of \(C^*\)-algebras via positive operators - MaRDI portal

A characterization of \(C^*\)-algebras via positive operators (Q1112297)

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scientific article; zbMATH DE number 4078033
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A characterization of \(C^*\)-algebras via positive operators
scientific article; zbMATH DE number 4078033

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    A characterization of \(C^*\)-algebras via positive operators (English)
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    1989
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    If B is a \(C^*\)-algebra an application of the Russo-Dye theorem shows that for all unital Banach algebras A with isometric involution each linear unital positive operator T:A\(\to B\) attains its operator norm at the unit element. We prove that this property in fact characterizes \(C^*\)-algebras in the class of all unital Banach *-algebras.
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    \(C^*\)-algebra
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    Russo-Dye theorem
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    isometric involution
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    linear unital positive operator
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    operator norm
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