1,773 research outputs found

    Solvability of the Dirichlet, Neumann and the regularity problems for parabolic equations with H\"older continuous coefficients

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    We establish the L2L^2-solvability of Dirichlet, Neumann and regularity problems for divergence-form heat (or diffusion) equations with H\"older-continuous diffusion coefficients, on bounded Lipschitz domains in Rn\mathbb{R}^n. This is achieved through the demonstration of invertibility of the relevant layer-potentials which is in turn based on Fredholm theory and a new systematic approach which yields suitable parabolic Rellich-type estimates

    Transference of local to global L2L^2 maximal estimates for dispersive partial differential equations

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    In this paper we give an elementary proof for transference of local to global maximal estimates for dispersive PDEs. This is done by transferring local L2L^2 estimates for certain oscillatory integrals with rough phase functions, to the corresponding global estimates. The elementary feature of our approach is that it entirely avoids the use of the wave packet techniques which are quite common in this context, and instead is based on scalings and classical oscillatory integral estimates.Comment: 10 page

    Análisis de la administración de las pequeñas y medianas empresas del sector marroquinero en Colombia: una mirada desde los cambios constantes de la economía global

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    Trabajo de investigaciónCon la apertura de mercados en los diferentes países se crea una entrada de productos mucho más económicos que los producidos en las regiones donde entra estos nuevos artículos o materias primas, esto conlleva que las empresas idean formas de producción más económicas arriesgando la calidad de los productos o entre en un estado de banca rotaINTRODUCCION 1.GENERALIDADES 2.RESULTADOS Y ANALISIS DE RESULTADOS 3.CONCLUSIONES 4.RECOMERNDACIONES BIBLIOGRAFIA ANEXOSPregradoIngeniero Industria

    Characterization of Banach valued BMO functions and UMD Banach spaces by using Bessel convolutions

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    In this paper we consider the space BMOo(R,X)BMO_o(\mathbb{R},X) of bounded mean oscillations and odd functions on R\mathbb{R} taking values in a UMD Banach space XX. The functions in BMOo(R,X)BMO_o(\mathbb{R},X) are characterized by Carleson type conditions involving Bessel convolutions and γ\gamma-radonifying norms. Also we prove that the UMD Banach spaces are the unique Banach spaces for which certain γ\gamma-radonifying Carleson inequalities for Bessel-Poisson integrals of BMOo(R,X)BMO_o(\mathbb{R},X) functions hold.Comment: 29 page

    Characterization of UMD Banach spaces by imaginary powers of Hermite and Laguerre operators

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    In this paper we characterize the Banach spaces with the UMD property by means of Lp-boundedness properties for the imaginary powers of the Hermite and Laguerre operators. In order to do this we need to obtain pointwise representations for the Laplace transform type multipliers associated with Hermite and Laguerre operators.Comment: 17 page

    Variable exponent Hardy spaces associated with discrete Laplacians on graphs

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    In this paper we develop the theory of variable exponent Hardy spaces associated with discrete Laplacians on infinite graphs. Our Hardy spaces are defined by square integrals, atomic and molecular decompositions. Also we study boundedness properties of Littlewood-Paley functions, Riesz transforms, and spectral multipliers for discrete Laplacians on variable exponent Hardy spaces

    Discrete harmonic analysis associated with ultraspherical expansions

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    We study discrete harmonic analysis associated with ultraspherical orthogonal functions. We establish weighted l^p-boundedness properties of maximal operators and Littlewood-Paley g-functions defined by Poisson and heat semigroups generated by certain difference operator. We also prove weighted l^p-boundedness properties of transplantation operators associated to the system of ultraspherical functions. In order to show our results we previously establish a vector-valued local Calder\'on-Zygmund theorem in our discrete setting

    Conical square functions associated with Bessel, Laguerre and Schr\"odinger operators in UMD Banach spaces

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    In this paper we consider conical square functions in the Bessel, Laguerre and Schr\"odinger settings where the functions take values in UMD Banach spaces. Following a recent paper of Hyt\"onen, van Neerven and Portal, in order to define our conical square functions, we use γ\gamma-radonifying operators. We obtain new equivalent norms in the Lebesgue-Bochner spaces Lp((0,),B)L^p((0,\infty ),\mathbb{B}) and Lp(Rn,B)L^p(\mathbb{R}^n,\mathbb{B}), 1<p<1<p<\infty, in terms of our square functions, provided that B\mathbb{B} is a UMD Banach space. Our results can be seen as Banach valued versions of known scalar results for square functions

    Solutions of Weinstein equations representable by Bessel Poisson integrals of BMO functions

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    We consider the Weinstein type equation Lλu=0\mathcal{L}_\lambda u=0 on (0,)×(0,)(0,\infty )\times (0,\infty ), where Lλ=t2+x2λ(λ1)x2\mathcal{L}_\lambda=\partial _t^2+\partial _x^2-\frac{\lambda (\lambda -1)}{x^2}, with λ>1\lambda >1. In this paper we characterize the solutions of Lλu=0\mathcal{L}_\lambda u=0 on (0,)×(0,)(0,\infty )\times(0,\infty ) representable by Bessel-Poisson integrals of BMO-functions as those ones satisfying certain Carleson properties

    Geografía y ocurrencia del delito: Las aportaciones disciplinarias al entendimiento espacial del crimen

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    El trabajo hace una revisión de las ventajas de las técnicas geográficas sobre las tradicionales para el análisis del crimen. Expone sus alcances, fuentes de información necesarias y de manera general la forma de interpretación de los datos
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