Revista de Matemáticas 14(1)
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Ítem Caracterización de espacios de Banach mediante desigualdades y el mapeo de dualidad(2009-02-25 00:00:00) Ugalde Gómez, William JavierUsing a result of C. E. Chidume, we present a shorter and improved proof of aresult of Xu and Roach on characterization of uniformly convex and uniformly smoothBanach spaces by the duality map and inequalities involving strictly increasing andstrictly decreasing functions.Keywords: Banach spaces, duality maps, uniformly convex spaces, uniformly smoothspaces, modulus of convexity, modulus of smoothness.Ítem Differentially closed fields of characteristic zero with a generic automorphism(2009-02-25 00:00:00) Bustamante Medina, Ronald F.Hrushovski showed that the theory of difference-differential fields of characteristiczero has a model-companion, which we shall denote DCFA. We give an axiomatizationfor DCFA and prove some important model-theoretic results as supersimplicity andelimination of imaginaries. We mention some properties of the fixed field and theconstant field of a model of DCFA.Keywords: Mathematical logic, model theory, differential fields, difference fieldsÍtem A note on Dirichlet and Fejér kernels(2009-02-25 00:00:00) López Bonilla, José; Vidal Beltrán, Sergio; Yalja Montiel, JesúsWe exhibit a trigonometric identity wich implies a link between the kernels ofDirichlet and Fejér.Ítem Valores propios asociados al operador de Hill unidimensional. Caso general.(2009-02-25 00:00:00) Cambronero, Santiago; Alfaro, MarcoWe study Hill’s equation with general boundary conditions and white noise potential.In [3] they solve the problem with Dirichlet conditions, leaving the general case unresolved.The problem is important both from the theoretical and the applied point of view, giventhe range of applications of the subject. Following [6], we give a description of thestandard brownian motion process, and mention some of its basic properties. We thenintroduce the equation to be studied, the remaining of the work being devoted to theanalysis of the asymptotic of eigenvalues.Keywords: Hill’s operator, boundary conditions, Brownian motion, eigenvalues.Ítem Estudio de opinión sobre el T.L.C. con EE.UU.(2009-02-25 00:00:00) Poltronieri Vargas, JorgeWe expose the results of an opinion survey on the Free Trade Agreement with theUnited States of America. The technique of Principal Component Analysis helped usto reveal the subjacent opinion in the Costarican comunity. The results show us agreat population’s preocupation about the implications of the trade, in the society.Keywords: Opinion structures, public opinion survey, principal component analysis, freetrade.Ítem Selección de Personal mediante Redes Neuronales Artificiales(2011-04-29 00:00:00) Acevedo Orduña, German Leonardo; Caicedo Bravo, Eduardo Francisco; Loaiza Correa, HumbertoWe study the personnel selection problem by the application of techniques of computing intelligence for the classification of psychological patterns. The system is based on the psychological test 16-PF, for the extraction of the First Order factors and the motivational distortion, for being used as entries in a pattern recognition algorithm that intends to predict behavior. Initially, we define the 16-PF test and the computational structures to be used. Then we describe the normalization and pattern extraction procedures, and finally, we provide experimental results for illustrating the performance of the classification techniques, which are analyzed in a problem of cadets selection for the Navy School Almirante Padilla.Ítem The Black-Scholes type financial models and the arbitrage opportunities(2009-02-25 00:00:00) Sukhomlin, NikolayBy using the conservation laws concept, we study certain financial models similar tothe Black–Scholes model. We show that without complement limitations such modelscan have two or more volatilities. This fact imposes several intrinsic limitations forthe dynamical system parameters in order to guarantee the correct definition.Keywords: Black–Scholes model, volatility, laws of conservation.