Elvis Ronald Valero Kari - Academia.edu (original) (raw)

Uploads

Papers by Elvis Ronald Valero Kari

Research paper thumbnail of Una condición recursiva para el problema inverso del autovalor para matrices simétricas no negativas

espanolEn este articulo presentamos una condicion sufiente y una condicion necesaria para el Prob... more espanolEn este articulo presentamos una condicion sufiente y una condicion necesaria para el Problema Inverso de Autovalores para Matrices Simetricas no Negativas. Esta condicion es independiente de los criterios de realizabilidad existentes. Este criterio es recursivo, es decir determina si una lista Λ= {λ1, …, λn, λn+1} es realizable por una matriz simetrica no negativa, si la lista μ = {μ1, ..., μn} asociada a Λ es realizable. Este resultado es facil de programar y mejora algunos criterios existentes. EnglishAbstract. In this paper we present a sufficient ondition and a necessary condition for Symmetri Nonnegative Inverse Eigenvalue Problem. This condition is independent of the existing realizability criteria. This criterion is recursive, that is, it determines whether a list Λ= {λ1, …, λn, λn+1} is realizable by a nonnegative symmetric matrix, if the list μ = {μ1, ..., μn} associated to Λ is realizable. This result is easy to program and improves some existing criteria. Keywords...

Research paper thumbnail of A recursive condition for the symmetric nonnegative inverse eigenvalue problem

Revista Integración, Aug 10, 2017

In this paper we present a sufficient condition and a necessary condition for Symmetric Nonnegati... more In this paper we present a sufficient condition and a necessary condition for Symmetric Nonnegative Inverse Eigenvalue Problem. This condition is independent of the existing realizability criteria. This criterion is recursive, that is, it determines whether a list Λ = {λ 1 , ..., λ n , λ n+1 } is realizable by a nonnegative symmetric matrix, if the list µ = {µ 1 , ..., µ n } associated to Λ is realizable. This result is easy to program and improves some existing criteria.

Research paper thumbnail of On Symmetric Nonnegative Matrices with Prescribed Spectrum1

In this paper we give a sufficient condition for the existence and construction of a symmetric no... more In this paper we give a sufficient condition for the existence and construction of a symmetric nonnegative matrix with prescribed spectrum, and a sufficient conditon for the existence and construction of a 4 × 4 symmetric nonnegative matrix with prescribed spectrum and diagonal entries. This last condition is independent of the sufficient condition given by Fiedler [LAA 9 (1974) 119-142]. We also give some partial answers on an open question of Guo [LAA 266 (1997) 261-270] about symmetric nonnegative matrices.

Research paper thumbnail of A simple approximation for the modified Bessel function of zero order I 0(x)

Journal of Physics: Conference Series

New efficient analytic approximations have been found for the modified zero-order Bessel function... more New efficient analytic approximations have been found for the modified zero-order Bessel functions I0(x). The method, used herein, improves prior techniques, such as multipoint quasi-rational approximations, MPQA. The present work is also an improvement of previous works, in the sense that the form of the approach is more efficient, that is, a smaller relative error is obtained using a lower number of parameters. As in the Pade method rational functions are used with coefficients determined from the powers series, but now also asymptotic expansions are also used simultaneously with that series, and consequently the rational functions have to be combined with elementary functions, in such a way, that the approach is a bridge between both expansions. The approximation now found is a rational function combined with a hyperbolic function. Only three parameters are needed to obtain a relative error smaller than 0.6 percent.

Research paper thumbnail of Una condición recursiva para el problema inverso del autovalor para matrices simétricas no negativas

espanolEn este articulo presentamos una condicion sufiente y una condicion necesaria para el Prob... more espanolEn este articulo presentamos una condicion sufiente y una condicion necesaria para el Problema Inverso de Autovalores para Matrices Simetricas no Negativas. Esta condicion es independiente de los criterios de realizabilidad existentes. Este criterio es recursivo, es decir determina si una lista Λ= {λ1, …, λn, λn+1} es realizable por una matriz simetrica no negativa, si la lista μ = {μ1, ..., μn} asociada a Λ es realizable. Este resultado es facil de programar y mejora algunos criterios existentes. EnglishAbstract. In this paper we present a sufficient ondition and a necessary condition for Symmetri Nonnegative Inverse Eigenvalue Problem. This condition is independent of the existing realizability criteria. This criterion is recursive, that is, it determines whether a list Λ= {λ1, …, λn, λn+1} is realizable by a nonnegative symmetric matrix, if the list μ = {μ1, ..., μn} associated to Λ is realizable. This result is easy to program and improves some existing criteria. Keywords...

Research paper thumbnail of A recursive condition for the symmetric nonnegative inverse eigenvalue problem

Revista Integración, Aug 10, 2017

In this paper we present a sufficient condition and a necessary condition for Symmetric Nonnegati... more In this paper we present a sufficient condition and a necessary condition for Symmetric Nonnegative Inverse Eigenvalue Problem. This condition is independent of the existing realizability criteria. This criterion is recursive, that is, it determines whether a list Λ = {λ 1 , ..., λ n , λ n+1 } is realizable by a nonnegative symmetric matrix, if the list µ = {µ 1 , ..., µ n } associated to Λ is realizable. This result is easy to program and improves some existing criteria.

Research paper thumbnail of On Symmetric Nonnegative Matrices with Prescribed Spectrum1

In this paper we give a sufficient condition for the existence and construction of a symmetric no... more In this paper we give a sufficient condition for the existence and construction of a symmetric nonnegative matrix with prescribed spectrum, and a sufficient conditon for the existence and construction of a 4 × 4 symmetric nonnegative matrix with prescribed spectrum and diagonal entries. This last condition is independent of the sufficient condition given by Fiedler [LAA 9 (1974) 119-142]. We also give some partial answers on an open question of Guo [LAA 266 (1997) 261-270] about symmetric nonnegative matrices.

Research paper thumbnail of A simple approximation for the modified Bessel function of zero order I 0(x)

Journal of Physics: Conference Series

New efficient analytic approximations have been found for the modified zero-order Bessel function... more New efficient analytic approximations have been found for the modified zero-order Bessel functions I0(x). The method, used herein, improves prior techniques, such as multipoint quasi-rational approximations, MPQA. The present work is also an improvement of previous works, in the sense that the form of the approach is more efficient, that is, a smaller relative error is obtained using a lower number of parameters. As in the Pade method rational functions are used with coefficients determined from the powers series, but now also asymptotic expansions are also used simultaneously with that series, and consequently the rational functions have to be combined with elementary functions, in such a way, that the approach is a bridge between both expansions. The approximation now found is a rational function combined with a hyperbolic function. Only three parameters are needed to obtain a relative error smaller than 0.6 percent.