Recent Submissions

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    On the growth of Hardy and Bergman norms of functions in the Dirichlet space  [Presentation]

    Vukotic, Dragan (Editorial Universidad de Sevilla, 2005)
    We review the Chang-Marshall inequality of Moser-Trudinger type for the Dirichlet space. We then use a weaker version of this result to derive a sharp asymptotic estimate for Hardy and Bergman norms of a Dirichlet function ...
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    On spectral structure of bounded linear operators on reflexive Banach spaces  [Presentation]

    Shkarin, Stanislav A.; Smolyanov, Oleg G. (Editorial Universidad de Sevilla, 2005)
    A descriptive characterization of point, continuous, and residual spectra of operators acting on a separable Hilbert space is obtained. The possible point spectra of bounded linear operators acting on lp, 1 < p < ∞ are ...
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    Composition operators on the weighed Bergman-Nevanlinna classes  [Presentation]

    Sharma, Somdatt D.; Sharma, Ajay K. (Editorial Universidad de Sevilla, 2005)
    In this paper we use an α-Carleson measure and a vanishing Carleson measure to characterize bounded and compact composition operators on weighted Bergman-Nevanlinna spaces.
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    Operators on Lp and the role of the image of the unit ball  [Presentation]

    Romero Moreno, María del Carmen (Editorial Universidad de Sevilla, 2005)
    Let p ∈ [1, +∞] such that its conjugate exponent q is not an even integer and let T be an operator defined on Lp(λ) with values in a Banach space. In this note we discuss how the image of the unit ball determines whether ...
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    Composition operators with linear fractional smbols and their adjoints  [Presentation]

    Martín Gómez, María José (Editorial Universidad de Sevilla, 2005)
    We characterize all linear fractional maps of the disk into itself in terms of their coefficients. We also prove the formula for the adjoint of a composition operator with a linear fractional symbol acting on the quotient ...
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    Toeplitz operators and division by inner functions  [Presentation]

    Girela Álvarez, Daniel; González Enríquez, Cristóbal Miguel; Peláez Márquez, José Ángel (Editorial Universidad de Sevilla, 2005)
    A subspace X of the Hardy space H1 is said to have the K-property if for any ψ ∈ H∞, the Toeplitz operator Tψ maps X into itself. This in turn implies that X also has the f-property. This means that h/I ∈ X whenever h ∈ X ...
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    Banach algebras with trivial cohomology  [Presentation]

    El Harti, Rachid (Editorial Universidad de Sevilla, 2005)
    A plausible conjecture is that Banach algebras with trivial cohomology have to be semisimple and finite dimensional. In this paper, we show that a Hermitian Banach ∗-algebra has trivial cohomology if and only if it is ...
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    A parametrization for the symbols of a Hankel type operator  [Presentation]

    Bermudo Navarrete, Sergio; Marcantognini, Stefania A. M.; Morán, María Dolores (Editorial Universidad de Sevilla, 2005)
    Hankel operators and their symbols, as generalized by V. Pták and P. Vrbová, are considered. In this more general framework, a linear operator X from a Hilbert space H1 to a Hilbert space H2 is said to be a Hankel operator ...
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    Volterra operators on spaces of analytic functions - a survey  [Presentation]

    Siskakis, Aristomenis (Editorial Universidad de Sevilla, 2005)
    We give a short and selective account of results known about operators of the form Vg(f)(z) = 1/z Z z 0 f(ζ)g0 (ζ) dζ, where g is analytic on the disc and the operator Tg = zVg acts on spaces of analytic functions.
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    Invariant subspaces of translation semigroups  [Presentation]

    Power, Stephen C. (Editorial Universidad de Sevilla, 2005)
    In these lectures I shall give an account of some recent results and open problems relating to subspaces of square integrable functions on the real line which are jointly invariant for a pair of semigroups of unitary ...
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    How large is a Riemann surface: the type problem  [Presentation]

    Drasin, David (Editorial Universidad de Sevilla, 2005)
    The uniformization theorem asserts that a simply-connected non-compact Riemann surface S is conformally equivalent to precisely one of the unit disk D or the finite complex plane C. While this result (nearly a century old) ...
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    Analytic contractions and boundary behaviour - an overview  [Presentation]

    Aleman, Alexandru; Richter, Stefan; Sundberg, Carl (Editorial Universidad de Sevilla, 2005)