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A Characterization of Compact-friendly Multiplication Operators

Y. A. Abramovich·C. D. Aliprantis·O. Burkinshaw·A. W. Wickstead
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Abstract

Answering in the affirmative a question posed in [Y.A.Abramovich, C.D.Aliprantis and O.Burkinshaw, Multiplication and compact-friendly operators, Positivity 1 (1997), 171--180], we prove that a positive multiplication operator on any $L_p$-space (resp. on a $C(Ω)$-space) is compact-friendly if and only if the multiplier is constant on a set of positive measure (resp. on a non-empty open set). In the process of establishing this result, we also prove that any multiplication operator has a family of hyperinvariant bands -- a fact that does not seem to have appeared in the literature before. This provides useful information about the commutant of a multiplication operator.

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Y. A. Abramovich, C. D. Aliprantis, O. Burkinshaw, A. W. Wickstead. 1999-03-23. A Characterization of Compact-friendly Multiplication Operators. https://arxiv.org/abs/math/9903139

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