Dilation theory and systems of simultaneous equations in the predual of an operator algebra. II (Q1058712)

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scientific article; zbMATH DE number 3901461
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Dilation theory and systems of simultaneous equations in the predual of an operator algebra. II
scientific article; zbMATH DE number 3901461

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    Dilation theory and systems of simultaneous equations in the predual of an operator algebra. II (English)
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    1986
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    Let T be a contraction on the Hilbert space \({\mathcal H}\) such that the weak*-closed algebra generated by T is isomorphic with the Hardy space \(H^{\infty}\) via the Sz.-Nagy-Foias functional calculus. We say that T has property \({\mathbb{A}}_{\aleph_ o}\) if for every family \(\{K_{ij}: 0\leq i,j<\infty \}\) of trace-class operators on \({\mathcal H}\) there exist vectors \(\{x_ i,y_ i: 0\leq i<\infty \}\) in \({\mathcal H}\) such that \(tr(T^ nK_{ij})=(T^ nx_ i,y_ j)\) for \(0\leq i,j,n<\infty\). We show that every contraction with property \({\mathbb{A}}_{\aleph_ 0}\) is reflexive, thus extending a previous result pertaining to a more restricted class of operators. [For part I see Mich. Math. J. 30, 335-354 (1983; Zbl 0541.47007).]
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    weak*-closed algebra
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    Hardy space
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    Sz.-Nagy-Foias functional calculus
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    trace-class operators
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