David P. Blecher

  1. Metric characterizations II.

    Authors: David P. Blecher, Matthew Neal
    Subjects: Operator Algebras
    Abstract

    The present paper is a sequel to our paper "Metric characterization of
    isometries and of unital operator spaces and systems". We characterize certain
    common objects in the theory of operator spaces (unitaries, unital operator
    spaces, operator systems, operator algebras, and so on), in terms which are
    purely linear-metric, by which we mean that they only use the vector space
    structure of the space and its matrix norms. In the last part we give some
    characterizations of operator algebras (which are not linear-metric in our
    strict sense described in the paper).

  2. A characterization and a generalization of W*-modules.

    Authors: David P. Blecher, Upasana Kashyap
    Subjects: Operator Algebras
    Abstract

    We give a new Banach module characterization of $W^*$-modules, also known as
    selfdual Hilbert $C^*$-modules over a von Neumann algebra. This leads to a
    generalization of the notion, and the theory, of W*-modules, to the setting
    where the operator algebras are $\sigma$-weakly closed algebras of operators on
    a Hilbert space. That is, we find the appropriate weak* topology variant of our
    earlier notion of {\em rigged modules}, and their theory, which in turn
    generalizes the notions of C*-module, and Hilbert space, successively.

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