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A geometric characterization of ring homomorphisms on \(f\)-rings - MaRDI portal

A geometric characterization of ring homomorphisms on \(f\)-rings (Q2847686)

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scientific article; zbMATH DE number 6207500
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English
A geometric characterization of ring homomorphisms on \(f\)-rings
scientific article; zbMATH DE number 6207500

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    11 September 2013
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    basic element
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    convex set
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    extreme point
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    \(f\)-ring
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    \(\ell\)-group
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    ring homomorphism
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    A geometric characterization of ring homomorphisms on \(f\)-rings (English)
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    Let \(A\) be an \(f\)-ring with identity and \(B\) an Archimedean \(f\)-ring. The authors consider group homomorphisms from \(A\) to \(B\) that map the identity to a fixed idempotent element \(w\) in \(B\). They show that such a mapping is a ring homomorphism if and only if it is an extreme point of the set of all such maps. They derive a characterization of such ring homomorphisms in terms of a Gelfand-type transform. They finally show that in case \(u=1\), the homomorphisms are (up to multiplicative constants) the basis elements of the \(\ell\)-group of all bounded group homomorphisms from \(A\) to \(\mathbb R\).
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