Combined Matrix of a Tridiagonal Toeplitz Matrix

Abstract

In this work, combined matrices of tridiagonal Toeplitz matrices are studied. The combined matrix is known as the Relative Gain Array in control theory. In particular, given a real tridiagonal Toeplitz matrix of order n, the characterization of its combined matrix as a bisymmetric and doubly quasi-stochastic matrix is studied. Furthermore, this paper addresses the inverse problem, that is, given a bisymmetric, doubly quasi-stochastic tridiagonal Jacobi matrix U of order n, determine under what conditions there exists a real tridiagonal Toeplitz matrix A such that its combined matrix is U.

Keywords

• tridiagonal Toeplitz matrix
• combined matrix
• doubly quasi-stochastic matrix
• Jacobi matrix
• linear algebra