Now showing items 21-37 of 37

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      On some random thin sets of integers  [Article]

      Li, Daniel; Queffélec, Hervé; Rodríguez Piazza, Luis (American Mathematical Society, 2008-01)
      We show how different random thin sets of integers may have different behaviour. First, using a recent deviation inequality of Boucheron, Lugosi and Massart, we give a simpler proof of one of our results in Some new thin ...
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      On the Muskat problem: global in time results in 2D and 3D  [Article]

      Constantin, Peter; Córdoba Gazolaz, Diego; Gancedo García, Francisco; Rodríguez Piazza, Luis; Strain, Robert M. (Johns Hopkins University Press, 2016-12)
      This paper considers the three dimensional Muskat problem in the stable regime. We obtain a conservation law which provides an L2 maximum principle for the fluid interface. We also show global in time existence for strong ...
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      Operadores de composición y clases de Schatten  [Final Degree Work]

      González Doña, Francisco Javier (2018)
      The main goal of this work is to characterize the membership of composition operators on the Hardy space H2 of the unit disk to the Schatten classes. Firstly, we will study the basic results for compact operators between ...
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      Operadores universales y subespacios invariantes  [Master's Thesis]

      González Doña, Francisco Javier (2019)
      The Invariant Subspace Problem is one of the most studied problems on Operator Theory in the last decades. In fact, it is still open in the Hilbert space setting. The purpose of this work is to present the most classic ...
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      Rango y propiedades de medidas vectoriales. Conjuntos p-Sidon p.s.  [PhD Thesis]

      Rodríguez Piazza, Luis (1991)
      La presente memoria trata dos campos diferentes del Análisis Matemático. La primera parte se inscribe en el marco del estudio de las Medidas Vectoriales. La segunda trata sobre algunos problemas de Análisis Armónico, en ...
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      Semigrupos de operadores de composición  [Master's Thesis]

      Rosales Tristancho, Abel (2017-09)
      The main problem we consider in this work is the study of semigroups of composition operators on spaces of analytic functions on the unit disc. Mainly, we focus on the problem in Hardy spaces, Hp(D), and Bergman spaces, ...
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      Some examples of compact composition operators on H2  [Article]

      Lefèvre, Pascal; Li, Daniel; Queffélec, Hervé; Rodríguez Piazza, Luis (Elsevier, 2008-12-01)
      We construct, in an essentially explicit way, various composition operators on H2 and study their compactness or their membership in the Schatten classes. We construct: non-compact composition operators on H2 whose symbols ...
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      Some new properties of composition operators associated with lens maps  [Article]

      Lefèvre, Pascal; Li, Daniel; Queffélec, Hervé; Rodríguez Piazza, Luis (Springer, 2013-05)
      We give examples of results on composition operators connected with lens maps. The first two concern the approximation numbers of those operators acting on the usual Hardy space H2. The last ones are connected with ...
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      Some new thin sets of integers in harmonic analysis  [Article]

      Li, Daniel; Queffélec, Hervé; Rodríguez Piazza, Luis (Springer, 2002-12)
      We randomly construct various subsets A of the integers which have both smallness and largeness properties. They are small since they are very close, in various senses, to Sidon sets: the continuous functions with spectrum ...
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      Some revisited results about composition operators on Hardy spaces  [Article]

      Lefèvre, Pascal; Li, Daniel; Queffélec, Hervé; Rodríguez Piazza, Luis (European Mathematical Society, 2012)
      We generalize, on one hand, some results known for composition operators on Hardy spaces to the case of Hardy-Orlicz spaces HΨ: construction of a “slow” Blaschke product giving a non-compact composition operator on ...
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      Some translation-invariant Banach function spaces which contain C0  [Article]

      Lefèvre, Pascal; Li, Daniel; Queffélec, Hervé; Rodríguez Piazza, Luis (Polish Academy of Sciences, Institute of Mathematics, 2004)
      We produce several situations where some natural subspaces of classical Banach spaces of functions over a compact abelian group contain the space c0.
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      Strongly compact algebras  [Article]

      Lacruz Martín, Miguel Benito; Lomonosov, Victor; Rodríguez Piazza, Luis (Real Academia de Ciencias Exactas, Fisicas y Naturales, 2006)
      An algebra of bounded linear operators on a Hilbert space is said to be strongly compact if its unit ball is relatively compact in the strong operator topology. A bounded linear operator on a Hilbert space is said to be ...
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      El teorema de Kahane-Katznelson-de Leeuw  [Final Degree Work]

      García Rosa, Ignacio (2019)
      A lo largo de este trabajo, nuestro objetivo será estudiar el tamaño de los coeficientes de Fourier en diferentes espacios de funciones. Para ello, en el primer capítulo recordamos definiciones y nociones básicas del ...
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      The canonical injection of the Hardy-Orlicz space HΨ into the Bergman–Orlicz space BΨ  [Article]

      Lefèvre, Pascal; Li, Daniel; Queffélec, Hervé; Rodríguez Piazza, Luis (Polish Academy of Sciences, Institute of Mathematics, 2011)
      We study the canonical injection from the Hardy-Orlicz space HΨ into the Bergman–Orlicz space BΨ..
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      Thin sets of integers in Harmonic analysis and p-stable random Fourier series  [Article]

      Lefèvre, Pascal; Li, Daniel; Queffélec, Hervé; Rodríguez Piazza, Luis (Springer, 2011-06)
      We investigate the behavior of some thin sets of integers defined through random trigonometric polynomial when one replaces Gaussian or Rademacher variables by p-stable ones, with 1 < p < 2. We show that in one case this ...
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      Two results on composition operators on the Dirichlet space  [Article]

      Li, Daniel; Queffélec, Hervé; Rodríguez Piazza, Luis (Elsevier, 2015-06-15)
      We show that the decay of approximation numbers of compact composition operators on the Dirichlet space D can be as slow as we wish. We also prove the optimality of a result of O. El-Fallah, K. Kellay, M. Shabankhah ...
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      Weak compactness and Orlicz spaces  [Article]

      Lefèvre, Pascal; Li, Daniel; Queffélec, Hervé; Rodríguez Piazza, Luis (Polish Academy of Sciences (Institute of Mathematics), 2008)
      We give new proofs that some Banach spaces have Peczynski's property (V)