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U-algebras and the Hahn–Banach extension theorem*

Published online by Cambridge University Press:  14 November 2011

Boris Lavrič
Affiliation:
Department of Mathematics, E.K. University of Ljubljana, Jadranska 19, Ljubljana 61000, Yugoslavia

Synopsis

An Archimedean unital f-algebra A is called a U-algebra if, for every aA, there exists an invertible element uA such that a = u |a|. Characterisations of a U-algebra are established. As an application, an extension theorem of Hahn–Banach type on modules over a U-algebra and over the complexification of a Dedekind complete unital f-algebra is given.

Type
Research Article
Copyright
Copyright © Royal Society of Edinburgh 1987

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