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arXiv · 0807.1045

$AC(\sigma)$ operators

Brenden Ashton·Ian Doust
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Abstract

In this paper we present a new extension of the theory of well-bounded operators to cover operators with complex spectrum. In previous work a new concept of the class of absolutely continuous functions on a nonempty compact subset $\sigma$ of the plane, denoted $AC(\sigma)$, was introduced. An $\AC(\sigma)$ operator is one which admits a functional calculus for this algebra of functions. The class of $AC(\sigma)$ operators includes all of the well-bounded operators and trigonometrically well-bounded operators, as well as all scalar-type spectral operators, but is strictly smaller than Berkson and Gillespie's class of $AC$ operators. This paper develops the spectral properties of $AC(\sigma)$ operators and surveys some of the problems which remain in extending results from the theory of well-bounded operators.

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Brenden Ashton, Ian Doust. 2008-07-07. $AC(\sigma)$ operators. https://arxiv.org/abs/0807.1045

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