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THE EFFECT OF MEMORY TERMS IN DIFFUSION PHENOMENA

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Journal of Computational Mathematics 2006年第1期24卷 91-102页

作者： A. Araújo J.A. Ferreira P. Oliveira departamento de matemática Universidade de Coimbra Portugal

In this paper the effect of integral memory terms in the behavior of diffusion phenomena is studied. The energy functional associated with different models is analyzed and stability inequalities are established. Approximation methods for the computation of the solution of the integro-differential equations are constructed. Numerical results are included.

关键词： Heat propagation Integro-differential equation Numerical approximation,Splitting method

Generalized Hardy Spaces

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Acta Mathematica Sinica,English Series 2010年第9期26卷 1673-1692页

作者： Alexandre ALMEIDA António M.CAETANO departamento de matemática Universidade de Aveiro

Hardy spaces with generalized parameter are introduced following the maximal characterization approach. As particular cases, they include the classical Hp spaces and the Hardy-Lorentz spaces H^p,q. Real interpolation results with function parameter are obtained, Based on them, the behavior of some classical operators is studied in this generalized setting.

关键词： Generalized Hardy spaces maximal functions Poisson kernel interpolation with function parameter Riesz potentials singular integrals

Landesman–Lazer Type Conditions and Multiplicity Results for Nonlinear Elliptic Problems with Neumann Boundary Values

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Acta Mathematica Sinica,English Series 2014年第2期30卷 229-250页

作者： Edcarlos Domingos DA SILVA Francisco Odair de PAIVA Universidade Federal de Gois Departamento de Matemtica Universidade Federal de So Carlos Departamento de Matemtica

We establish the existence and multiplicity of solutions for Steklov problems under non- resonance or resonance conditions using variational methods. In our main theorems, we consider a weighted eigenvalue problem of ... 详细信息

关键词： Neumann-Steklov eigenvalue problems resonance Landesman-Lazer conditions

Proportionally Modular Diophantine Inequalities and Their Multiplicity

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Acta Mathematica Sinica,English Series 2010年第11期26卷 2059-2070页

作者： José Carlos ROSALES Manuel Batista BRANCO Paulo VASCO departamento de lgebra Universidad de Granada departamento de matemática departamento de matemática Universidade de Trás-os-Montes e Alto Douro

Let I be an interval of positive rational numbers. Then the set S （I） = T ∩ N, where T is the submonoid of （Q0＋, ＋） generated by T, is a numerical semigroup. These numerical semigroups are called proportionally modular and can be characterized as the set of integer solutions of a Diophantine inequality of the form ax rood b 〈 cx. In this paper we are interested in the study of the maximal intervals I subject to the condition that S （I） has a given multiplicity. We also characterize the numerical semigroups associated with these maximal intervals.

关键词： Numerical semigroup Diophantine inequality multiplicity Frobenius number

Modified Hawking effect from generalized uncertainty principle

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Communications in Theoretical Physics 2021年第1期73卷 62-67页

作者： Jaume Giné departament de matemàtica Universitat de LleidaCataloniaSpain

We use the generalized uncertainty principle to compute the first correction to the Hawking temperature associated to Hawking *** this value we obtain a new evaporation time and entropy of any Schwarzschild black hole... 详细信息

关键词： Hawking effect quantum fluctuations uncertainty principle

Inequalities for the Extended Best Polynomial Approximation Operator in Orlicz Spaces

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Acta Mathematica Sinica,English Series 2019年第2期35卷 185-203页

作者： Sonia ACINAS Sergio FAVIER Felipe ZO departamento de matemática Facultad de Ciencias y Exactas NaturalesUniversidad Nacional de La Pampa Instituto de matemática Aplicada San Luis IMASLUniversidad Nacional de San Luis and CONICET departamento de matemática Universidad Nacional de San Luis

In this paper we pursue the study of the best approximation operator extended from L~Φ to L~φ, where φ denotes the derivative of the function Φ. We get pointwise convergence for the coefficients of the extended best approximation polynomials for a wide class of function f, closely related to the Calder′on–Zygmund class t_m^p(x) which had been introduced in 1961. We also obtain weak and strong type inequalities for a maximal operator related to the extended best polynomial approximation and a norm convergence result for the coefficients is derived. In most of these results, we have to consider Matuszewska–Orlicz indices for the function φ.

关键词： Orlicz spaces extended best polynomial approximation pointwise and norm convergence weak and strong type inequalities Orlicz indices

On the Restricted Arc-connectivity of s-geodetic Digraphs

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Acta Mathematica Sinica,English Series 2010年第10期26卷 1865-1876页

作者： Camino BALBUENA Pedro GARCíA-VZQUEZ departament de matemàtica Aplicada Ⅲ Universitat Politècnica de Catalunya departamento de matemática Aplicada I Universidad de Sevilla E.T.S. de Arquitectura

For a strongly connected digraph D the minimum ,cardinality of an arc-cut over all arc-cuts restricted arc-connectivity λ′（D） is defined as the S satisfying that D - S has a non-trivial strong component D1 such that D - V（D1） contains an arc. Let S be a subset of vertices of D. We denote by w＋（S） the set of arcs uv with u ∈ S and v S, and by w-（S） the set of arcs uv with u S and v ∈ S. A digraph D = （V, A） is said to be λ′-optimal if λ′（D） =ξ′（D）, where ξ′（D） is the minimum arc-degree of D defined as ξ（D） = min {ξ′（xy）： xy ∈ A}, and ξ′（xy） = min（｜ω＋（{x,y}）｜, ｜w-（{x,y}）｜, ｜w＋（x） ∪ w- （y）｜, ｜w- （x） ∪ω＋（y）｜}. In this paper a sufficient condition for a s-geodetic strongly connected digraph D to be λ′-optimal is given in terms of its diameter. Furthermore we see that the h-iterated line digraph Lh（D） of a s-geodetic digraph is λ′-optimal for certain iteration h.

关键词： Restricted arc-connectivity arc-cut diameter s-geodetic digraph line digraph

Noether conserved quantities and Lie point symmetries of difference Lagrange-Maxwell equations and lattices

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Chinese Physics B 2009年第7期18卷 2634-2641页

作者：傅景礼聂宁明黄健飞 Jiménez Salvador 唐贻发 Vzquez Luis 赵维加 Institute of Mathematical Physics Zhejiang Sci-Tech University State Key Laboratory of Scientific and Engineering Computing ICMSECAcademy of Mathematics and Systems ScienceChinese Academy of Sciences department of Mathematics Qingdao University departamento de matema'tica Aplicada TTII E.T.S.I.Telecomunicacio'nUniversidad Polit'ecnica de Madrid28040-MadridSpain departamento de matemática Aplicada Facultad de MatemáticasInstituto de Matemática Interdisciplinar(IMI)Universidad Complutense de Madrid28040-MadridSpain departamento de matemática Aplicada Facultad de InformáticaInstituto de Matemática Interdisciplinar(IMI)Universidad Complutense de Madrid28040-MadridSpain

This paper presents a method to find Noether-type conserved quantities and Lie point symmetries for discrete mechanico-electrical dynamical systems,which leave invuriant the set of solutions of the corresponding difference scheme. This approach makes it possible to devise techniques for solving the Lagrange Maxwell equations in differences which correspond to mechanico-electrical systems,by adapting existing differential *** particular,it obtains a new systematic method to determine both the one-parameter Lie groups and the discrete Noether conserved quantities of Lie point symmetries for mechanico-electrical *** an application,it obtains the Lie point symmetries and the conserved quantities for the difference equation of a model that represents a capacitor microphone.

关键词： Lagrange Maxwell equation Lie point symmetry discrete mechanico-electrical system conserved quantity

A critique of supernova data analysis in cosmology

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Research in Astronomy and Astrophysics 2010年第12期10卷 1195-1198页

作者： Ram Gopal Vishwakarma Jayant V. Narlikar Unidad académica de matemáticas Universidad Autónoma de Zacatecas Inter-University Centre for Astronomy and Astrophysics

Observational astronomy has shown significant growth over the last decade and has made important contributions to cosmology. A major paradigm shift in cosmology was brought about by observations of Type Ia supernovae. The notion that the universe is accelerating has led to several theoretical challenges. Unfortunately, although high-quality supernovae data-sets are being produced, their statistical anal- ysis leaves much to be desired. Instead of using the data to directly test the model, several studies seem to concentrate on assuming the model to be correct and limiting themselves to estimating model parameters and internal errors. As shown here, the important purpose of testing a cosmological theory is thereby vitiated.

关键词： cosmology: observations -- supernovae Ia: general