Explicit inverse of a tridiagonal (p,r)-Toeplitz matrix

We have named tridiagonal (p,r)–Toeplitz matrix to those tridiagonal matrices in which each diagonal is a quasi–periodic sequence, d(p+j)=rd(j), so with period p¿N but multiplied by a real number r. We present here the necessary and sufficient conditions for the invertibility of this kind of matrice...

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Detalles Bibliográficos
Autores: Encinas Bachiller, Andrés Marcos|||0000-0001-5588-0373, Jiménez Jiménez, María José|||0000-0003-3502-462X
Tipo de recurso: artículo
Fecha de publicación:2017
País:España
Institución:Universitat Politècnica de Catalunya (UPC)
Repositorio:UPCommons. Portal del coneixement obert de la UPC
Idioma:inglés
OAI Identifier:oai:upcommons.upc.edu:2117/106362
Acceso en línea:https://hdl.handle.net/2117/106362
https://dx.doi.org/10.1016/j.laa.2017.06.010
Access Level:acceso abierto
Palabra clave:Toeplitz matrices
Differential equations, Linear
tridiagonal matrices
quasi–periodic sequences
second order linear difference equations
boundary value problems
discrete Schrödinger operator
Toeplitz, Matrius de
Equacions diferencials lineals
Classificació AMS::15 Linear and multilinear algebra
matrix theory
Classificació AMS::31 Potential theory
Classificació AMS::39 Difference and functional equations::39A Difference equations
Àrees temàtiques de la UPC::Matemàtiques i estadística::Equacions diferencials i integrals::Equacions en diferències
Descripción
Sumario:We have named tridiagonal (p,r)–Toeplitz matrix to those tridiagonal matrices in which each diagonal is a quasi–periodic sequence, d(p+j)=rd(j), so with period p¿N but multiplied by a real number r. We present here the necessary and sufficient conditions for the invertibility of this kind of matrices and explicitly compute their inverse. The techniques we use are related with the solution of boundary value problems associated to second order linear difference equations. These boundary value problems can be expressed throughout the discrete Schrödinger operator and their solutions can be computed using recent advances in the study of linear difference equations with quasi–periodic coefficients. The conditions that ensure the uniqueness solution of the boundary value problem lead us to the invertibility conditions for the matrix, whereas the solutions of the boundary value problems provides the entries of the inverse matrix.