Papers by Julio cesar Castro benitez
Applied Mathematics Letters, 2011
Let P and Q be two complex matrices satisfying P 2 = P and Q 2 = Q. If a, b are nonzero complex n... more Let P and Q be two complex matrices satisfying P 2 = P and Q 2 = Q. If a, b are nonzero complex numbers such that aP + bQ is diagonalizable, we relation the spectrum of aP + bQ with the spectrum of P − Q, P Q, P QP and P Q − QP .
Applied Mathematics Letters, 2006
In this paper we characterize the matrices A with the following property: for each ε > 0 there ex... more In this paper we characterize the matrices A with the following property: for each ε > 0 there exists k ∈ N such that A k − I < ε for a given matrix norm. This characterization is applied to the theory of unitary, hermitian nonnegative, positive and stochastic matrices.
Linear Algebra and its Applications, 2005
We extend generalized projectors (introduced by Groß and Trenkler in [Linear Algebra Appl. (1997)... more We extend generalized projectors (introduced by Groß and Trenkler in [Linear Algebra Appl. (1997) 264]) to k-generalized projectors and we characterize them obtaining results in the aforesaid paper as a consequence. Moreover, we list all situations when a linear combination of commuting k-generalized projectors is a k-generalized projector. The method for obtaining this result permits to give a revisited version of the main result by Baksalary and Baksalary in [Linear Algebra and its Appl. (Article in press)]. In addition, the case of orthogonal projectors is also analyzed.
Revista Cubana De Pediatria, Jun 1, 2013
Conclusiones: la imipramina fue eficaz en la mayoría de los pacientes, pues desapareció totalment... more Conclusiones: la imipramina fue eficaz en la mayoría de los pacientes, pues desapareció totalmente la sintomatología.
Mapping of human chromosome 22 by hybridization
Genomics, 1990
PO7-178 Lescogen Study: Association of Genetic Profiles and Environmental Factors in Response to Fluvastatin Treatment in Hypercholesterolemic Patients
Atherosclerosis Supplements, 2007
{k}-Group Periodic Matrices
SIAM Journal on Matrix Analysis and Applications, 2006
In this paper we deal with two problems related to {k}-group periodic matrices (ie, $A^{\#} = A^{... more In this paper we deal with two problems related to {k}-group periodic matrices (ie, $A^{\#} = A^{k-1}$, where $A^{\#}$ is the group inverse of a matrix A). First, we give different characterizations of {k}-group periodic matrices. Later, we present characterizations of the {k}-group ...
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Papers by Julio cesar Castro benitez