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Geometrical Methods for Solving of Fully Nonlinear Partial Differential Equations, by P. Popivanov
http://hdl.handle.net/10525/3491
Title: Geometrical Methods for Solving of Fully Nonlinear Partial Differential Equations, by P. Popivanov<br/><br/>Authors: Kutev, Nikolai<br/><br/>Abstract: 2000 Mathematics Subject Classification: 35-02, 53-02, 35B65, 35C05, 35F20, 35G25, 35L60,57R45, 58C28, 76J05.<br/><br/>Description: [Kutev Nikolai; Кутев Николай]Selected Papers, I, II by Nikola Obrechkoff
http://hdl.handle.net/10525/3490
Title: Selected Papers, I, II by Nikola Obrechkoff<br/><br/>Authors: Rusev, P.<br/><br/>Abstract: 2000 Mathematics Subject Classification: 00-02,00B60,01A75.<br/><br/>Description: [Rusev P.; Rusev Petăr; Rusev Peter; Russev P.; Russev Peter; Русев Петр; Русев Петър]A survey on the kissing numbers
http://hdl.handle.net/10525/3489
Title: A survey on the kissing numbers<br/><br/>Authors: Boyvalenkov, Peter; Dodunekov, Stefan; Musin, Oleg<br/><br/>Abstract: The maximum possible number of non-overlapping unit spheres that can touch a unit sphere in n dimensions is called kissing number. The problem for finding kissing numbers is closely connected to the more general problems of finding bounds for spherical codes and sphere packings. We survey old and recent results on the kissing numbers keeping the generality of spherical codes. 2010 Mathematics Subject Classification: 52C17, 94B65.<br/><br/>Description: [Boyvalenkov Peter; Бойваленков Петър]; [Dodunekov Stefan;Додунеков Стефан]In Memoriam - Stefan Manev Dodunekov (1945-2012)
http://hdl.handle.net/10525/3488
Title: In Memoriam - Stefan Manev Dodunekov (1945-2012)Bi-Characteristic Curves of Body and Surface Waves and Application in Geophysics
http://hdl.handle.net/10525/3487
Title: Bi-Characteristic Curves of Body and Surface Waves and Application in Geophysics<br/><br/>Authors: Boyadzhiev, Georgi<br/><br/>Abstract: In this paper is given a new approach to 3D modelling of elastic piecewise homogeneous media, in particular Earth crust and upper Mantle. The method is based on the principle of tomography with Earthquake as a source of the signal and at least three receiver stations on the surface. The wave propagation in such media is described by a system of three strongly coupled hyperbolic equations with piece-wise constant coefficients. The characteristic set and bi-characteristic curves are computed in a homogeneous half-space with free boundary as well as the formulae of reflection and diffraction of the bi-characteristics on the internal boundaries of the media. Applications of the characteristic set and bi-characteristic curves for the inverse problem in geophysics and Earth modelling are given. 2010 Mathematics Subject Classification: 35L53, 35Q86, 86A15.<br/><br/>Description: [Boyadzhiev Georgi; Бояджиев Георги]Hardy-Type Inequalities with Weights
http://hdl.handle.net/10525/3486
Title: Hardy-Type Inequalities with Weights<br/><br/>Authors: Fabricant, Alexander; Kutev, Nikolai; Rangelov, Tsviatko<br/><br/>Abstract: Hardy-type inequality with weights is derived in abstract form. Particular cases are presented to demonstrate the applicability of the method and to show generalizations of existing results. Sharpness of inequalities is proved and the results are illustrated with several examples. 2010 Mathematics Subject Classification: 26D10.<br/><br/>Description: [Fabricant Alexander; Фабрикант Александър]; [Kutev Nikolai; Кутев Николай]; [Rangelov Tsviatko; Рангелов Цвятко]Finite Time Blow up of the Solutions to Nonlinear Klein-Gordon Equation with Arbitrary High Positive Initial Energy
http://hdl.handle.net/10525/3485
Title: Finite Time Blow up of the Solutions to Nonlinear Klein-Gordon Equation with Arbitrary High Positive Initial Energy<br/><br/>Authors: Kutev, N.; Kolkovska, N.; Dimova, M.<br/><br/>Abstract: 2010 Mathematics Subject Classification: 35L05, 35L15.<br/><br/>Description: [Kutev N.; Кутев Н.]; [Kolkovska N.; Колковска Н.]; [Dimova M.; Димова М.]Mean Value Theorems for Analytic Functions
http://hdl.handle.net/10525/3484
Title: Mean Value Theorems for Analytic Functions<br/><br/>Authors: Markov, Lubomir<br/><br/>Abstract: We prove a sharper Evard-Jafari Theorem, various mean value theorems, and an improved version of the Davitt-Powers-Riedel-Sahoo Theorem. 2010 Mathematics Subject Classification: 30C15.<br/><br/>Description: [Марков Любомир; Markov Lubomir]On the Poisson-Charlier Polynomials
http://hdl.handle.net/10525/3483
Title: On the Poisson-Charlier Polynomials<br/><br/>Authors: Özmen, Nejla; Erkuş-Duman, Esra<br/><br/>Abstract: In this paper the Poisson-Charlier polynomials are introduced. Some of their recurrence relations are presented. Various families of bilinear and bilateral generating functions for these polynomials are derived. Furthermore, some special cases of the results are presented in this study. 2010 Mathematics Subject Classification: 33C45.Notes on Optimality Conditions Using Newton Diagrams and Sums of Squares
http://hdl.handle.net/10525/3482
Title: Notes on Optimality Conditions Using Newton Diagrams and Sums of Squares<br/><br/>Authors: Sekiguchi, Yoshiyuki<br/><br/>Abstract: We consider relationships between optimality conditions using Newton diagrams and sums of squares of polynomials and power series. 2010 Mathematics Subject Classification: 90C46, 13J30, 14M25.Convolutional Calculus of Dimovski and QR-regularization of the Backward Heat Problem
http://hdl.handle.net/10525/3481
Title: Convolutional Calculus of Dimovski and QR-regularization of the Backward Heat Problem<br/><br/>Authors: Bazhlekova, Emilia<br/><br/>Abstract: The final value problem for the heat equation is known to be ill-posed. To deal with this, in the method of quasi-reversibility (QR), the equation or the final value condition is perturbed to form an approximate well-posed problem, depending on a small parameter ε. In this work, four known quasi-reversibility techniques for the backward heat problem are considered and the corresponding regularizing problems are treated using the convolutional calculus approach developed by Dimovski (I.H. Dimovski, Convolutional Calculus, Kluwer, Dordrecht, 1990). For every regularizing problem, applying an appropriate bivariate convolutional calculus, a Duhamel-type representation of the solution is obtained. It is in the form of a convolution product of a special solution of the problem and the given final value function. A non-classical convolution with respect to the space variable is used. Based on the obtained representations, numerical experiments are performed for some test problems. 2010 Mathematics Subject Classification: 35C10, 35R30, 44A35, 44A40.<br/><br/>Description: [Bazhlekova Emilia; Бажлекова Емилия]Koszul Duality for Locally Constant Factorization Algebras
http://hdl.handle.net/10525/3480
Title: Koszul Duality for Locally Constant Factorization Algebras<br/><br/>Authors: Matsuoka, Takuo<br/><br/>Abstract: Generalizing Jacob Lurie’s idea on the relation between the Verdier duality and the iterated loop space theory, we study the Koszul duality for locally constant factorization algebras. We formulate an analogue of Lurie’s “nonabelian Poincaré duality” theorem (which is closely related to earlier results of Graeme Segal, of Dusa McDuff, and of Paolo Salvatore) in a symmetric monoidal stable infinity 1-category carefully, using John Francis’ notion of excision. Its proof depends on our study of the Koszul duality for En-algebras in [12]. As a consequence, we obtain a Verdier type equivalence for factorization algebras by a Koszul duality construction. 2010 Mathematics Subject Classification: 55M05, 16E40, 57R56, 16D90.Summability Methods in Weighted Approximation to Derivatives of Functions
http://hdl.handle.net/10525/3479
Title: Summability Methods in Weighted Approximation to Derivatives of Functions<br/><br/>Authors: Küçük, Nisa; Duman, Oktay<br/><br/>Abstract: In this paper, we use summability methods on the approximation to derivatives of functions by a family of linear operators acting on weighted spaces. This point of view enables us to overcome the lack of ordinary convergence in the approximation. To support this idea, at the end of the paper, we will give a sequence of positive linear operators obeying the arithmetic mean approximation (or, approximation with respect to the Cesàro method) although it is impossible in the usual sense. Some graphical illustrations are also provided. 2010 Mathematics Subject Classification: 41A30, 42B08, 47B38.EPW Sextics and Hilbert Squares of K3 Surfaces
http://hdl.handle.net/10525/3478
Title: EPW Sextics and Hilbert Squares of K3 Surfaces<br/><br/>Authors: Iliev, Atanas; Madonna, Carlo<br/><br/>Abstract: 2010 Mathematics Subject Classification: 14J35, 14F05.<br/><br/>Description: [Iliev Atanas; Илиев Атанас]Evolution Equations for the Stefan Problem
http://hdl.handle.net/10525/3477
Title: Evolution Equations for the Stefan Problem<br/><br/>Authors: Lukarevski, Martin<br/><br/>Abstract: We study particular kind of Stefan problem and use the theory of abstract quasilinear evolution equations for its solution. 2010 Mathematics Subject Classification: 35R35, 35B65, 35J70.Preface
http://hdl.handle.net/10525/3476
Title: Preface<br/><br/>Authors: Editors