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arXiv · 1804.08960

Similarity problems, Folner sets and isometric representations of amenable semigroups

Catalin Badea·Laurian Suciu
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Abstract

We revisit Sz.-Nagy's criteria for similarity of Hilbert space bounded linear operators to isometries or unitaries and present new ones. We also discuss counterparts of the Dixmier-Day theorem concerning bounded representations of amenable groups and semigroups. We highlight the role of Folner sets in similarity problems in both settings of unimodular, $σ$-compact, amenable groups and in discrete semigroups possessing the Strong Folner condition (SFC).

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BibTeXRIS

Catalin Badea, Laurian Suciu. 2018-10-03. Similarity problems, Folner sets and isometric representations of amenable semigroups. https://doi.org/10.1007/s00009-018-1294-6

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