# Remarks on Commuting Exponentials in Banach Algebras

## Proceedings of the American Mathematical Society / v.127 no.5. 1999, pp.1337-1338 window.___gcfg = {lang: 'ko'}; (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/platform.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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Abstract : Suppose that a and b are elements of a complex unital Banach algebra such that the spectra of a and b are 2 $\pi$ i-congruence-free. E.M.E. Wermuth has shown that then e $^{a}$ e $^{b}$ = elt;LA e $^{b}$ e $^{a}$ implies that ab = ba. In this note we use two elementary facts concerning inner derivations on Banach algebras to give a very short proof of Wermuths result.

Keyword : Primary 46H99 . Commuting exponentials

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