Mostrando ítems 41-60 de 619

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    Pointwise Estimates for $ 3$ -monotone Approximation 

    Bondarenko, A.; Leviatan, D.; Prymak, A. (Fecha de publicación: 2011-01-01)

    We prove that for a $ 3$ -monotone function $ F\in C[-1,1]$ , one can achieve the pointwise estimates \[ |F(x)-\Psi(x)|\le c\omega_3(F,\rho_n(x)), \quad x\in[-1,1], \] where $ \rho_n(x):=\frac1{n^2}+\frac{\sqrt{1-x^2}}n$ ...

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    On orders of approximation of the generalized Nikol'\''skii--Besov class in Lorentz spaces 

    Akishev, G. (Fecha de publicación: 2016-01-01)

    This paper considers the Lorentz space with mixed norm of periodic functions of many variables and of the generalized Nikol'\''skii--Besov classes. Estimates for the order of approximation of the generalized Nikol'\''skii--Besov ...

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    Pitt'\''s and Boas'\'' inequalities for Fourier and Hankel transforms 

    De Carli, L.; Gorbachev, D.; Tikhonov, S. (Fecha de publicación: 2014-01-01)

    We prove Pitt and Boas'\'' type inequalities for products of radial functions and spherical harmonics in $ \R^n$ . In the process, we obtain upper and lower estimates of the operator norm of the Hankel transform with power ...

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    Parabolic equations in time dependent domains 

    Calvo, J.; Novaga, M.; Orlandi, G. (Fecha de publicación: 2015-01-01)

    We show existence and uniqueness results for nonlinear parabolic equations in noncylindrical domains with possible jumps in the time variable.

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    Peaks and Jumps Reconstruction with B-Splines Scaling Functions 

    Ortiz-Gracia, L.; Masdemont, J.J. (Fecha de publicación: 2012-01-01)

    We consider a methodology based in B-splines scaling functions to numerically invert Fourier or Laplace transforms. The methodology is particularly well suited when the original function or its derivatives present peaks ...

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    Gorenstein homological algebra and universal coefficient theorems 

    Dell'Ambrogio, I.; Stevenson, G.; Šťovíček, J. (Fecha de publicación: 2015-01-01)

    We study criteria for a ring -- or more generally, for a small category -- to be Gorenstein and for a module over it to be of finite projective dimension. The goal is to unify the universal coefficient theorems found in ...

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    Description of interpolation spaces for the pair of local Morrey-type spaces and their generalizations 

    Burenkov, V.I.; Darbayeva, D.K.; Nursultanov, E.D. (Fecha de publicación: 2014-01-01)

    We consider the real interpolation method and prove that for general local Morrey-type spaces, in the case when they have the same integrability parameter, the interpolation spaces are again general local Morrey-type spaces ...

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    Multi-tiling and Riesz bases 

    Grepstad, S.; Lev, N. (Fecha de publicación: 2014-01-01)

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    HIGH ORDER AND ENERGY PRESERVING DISCONTINUOUS GALERKIN METHODS FOR THE VLASOV-POISSON SYSTEM 

    Ayuso de Dios, B.; Hajian, S. (Fecha de publicación: 2012-01-01)

    We present a computational study for a family of discontinuous Galerkin methods for the one dimensional Vlasov-Poisson system, recently introduced in \cite{acs0}. We introduce a slight modification of the methods to allow ...

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    Highest weight categories and recollements 

    Krause, H. (Fecha de publicación: 2015-01-01)

    We provide several equivalent descriptions of a highest weight category using recollements of abelian categories. The settings for this are abelian length categories and $ k$ -linear exact categories, where $ k$ denotes ...

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    Hamiltonian stability in some open surfaces with simple singularities 

    Rabanal, R. (Fecha de publicación: 2015-01-01)

    We complement to some open surfaces with singularities the basic characterization theorem obtained by Jarque--Nitecki [Ergod. Th. \& Dynam Sys. \textbf{20} (2000) 775--799] for Hamiltonian flows in the Euclidean plane which ...

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    On an extension of the notion of Reedy category 

    Berger, C.; Moerdijk, I. (Fecha de publicación: 2008-01-01)

    We extend the classical notion of a Reedy category so as to allow non-trivial automorphisms. Our extension includes many important examples occuring in topology such as Segal'\''s category $ \Gamma$ , or the total category ...

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    Hopf bifurcation at infinity and dissipative vector fields of the plane 

    Alarcón, B.; Rabanal, R. (Fecha de publicación: 2014-01-01)

    We describe some families of differentiable vector fields with the Hopf bifurcation at infinity, without assuming the continuous differentiability. These vector fields have isolated singular points on the plane, and the ...

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    On the limit cycles of a class of Kukles type differential systems 

    Rabanal, R. (Fecha de publicación: 2014-01-01)

    We study the limit cycles of two families of differential systems in the plane. These systems are obtained by polynomial perturbations with arbitrary degree on the second component of the standard linear center. In this ...

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    Mathematical modelling of heat exchange in flash tank heat exchanger cascades 

    Korobeinikov, A.; McCarthy, J.; Mooney, E.; Semkov, K. (Fecha de publicación: 2014-01-01)

    Flash tank evaporation combined with a condensing heat exchanger can be used when heat exchange is required between two streams, where at least one of these streams is difficult to handle (tends severely to scale, foul, ...

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    Conjugacy in Houghton'\''s Groups 

    Antolín, Y.; Burillo, J.; Martino, A. (Fecha de publicación: 2014-01-01)

    Let $ n\in \N$ . Houghton'\''s group $ H_n$ is the group of permutations of $ \{1,\dots, n\}\times \N$ , that eventually act as a translation in each copy of $ \N$ . We prove the solvability of the conjugacy problem and ...

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    Graded C*-algebras, graded K-theory, and twisted P-graph C*-algebras 

    Kumjian, A.; Pask, D.; Sims, A. (Fecha de publicación: 2017-01-01)

    We develop methods for computing the graded $ K$ -theory of $ C^*$ -algebras as defined in terms of Kasparov theory. We establish graded versions of Pimsner'\''s six-term sequences for graded Hilbert bimodules whose left ...

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    Models order reduction and equivalence: Paradox of enrichment is a 3-dim bacteriophages dynamics model as case study 

    Sobolev, V.; Shchepakina, E.; Korobeinikov, A. (Fecha de publicación: 2015-01-01)

    The paradox of enrichment in a three-dimensional model for bacteriophage dynamics with a free infection stage of the phage and bilinear incident rate is considered. An application of the technique of singular perturbation ...

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    Efficient VaR and Expected Shortfall computations for non-linear portfolios within the delta-gamma approach 

    Ortiz-Gracia, L.; Oosterlee, C.W. (Fecha de publicación: 2014-01-01)

    We present four numerical methods to compute the Value-at-Risk and Expected Shortfall risk measure values of portfolios with financial options. The numerical methods are based on either wavelets or Fourier cosine approximations ...

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    Mathematical modeling of the development of specialization in viral evolution 

    Korobeinikov, A.; Nurtay, A. (Fecha de publicación: 2016-01-01)