Mihai Putinar

  1. A Striktpositivstellensatz for measurable functions (corrected version).

    Authors: Mihai Putinar
    Subjects: Functional Analysis
    Abstract

    A weighted sums of squares decomposition of positive Borel measurable
    functions on a bounded Borel subset of the Euclidean space is obtained via
    duality from the spectral theorem for tuples of commuting self-adjoint
    operators. The analogous result for polynomials or certain rational functions
    was amply exploited during the last decade in a variety of applications.

  2. Positivity and optimization for semi-algebraic functions.

    Authors: Mihai Putinar, Jean-Bernard Lasserre
    Subjects: Optimization and Control
    Abstract

    We describe algebraic certificates of positivity for functions belonging to a
    finitely generated algebra of Borel measurable functions, with particular
    emphasis to algebras generated by semi-algebraic functions. In which case the
    standard global optimization problem with constraints given by elements of the
    same algebra is reduced via a natural change of variables to the better
    understood case of polynomial optimization. A collection of simple examples and
    numerical experiments complement the theoretical parts of the article.

  3. Unitary invariants for Hilbert modules of finite rank.

    Authors: Shibananda Biswas, Gadadhar Misra, Mihai Putinar
    Subjects: Spectral Theory
    Abstract

    A refined notion of curvature for a linear system of Hermitian vector spaces,
    in the sense of Grothendieck, leads to the unitary classification of a large
    class of analytic Hilbert modules. Specifically, we study Hilbert sub-modules,
    for which the localizations are of finite (but not constant) dimension, of an
    analytic function space with a reproducing kernel.

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