Minimal Nonsquare J-Spectral Factorization, Generalized Bezoutians and Common Zeros for Rational Matrix Functions

The problem that we solve in this paper is to find (square or nonsquare) minimal J-spectral factors of a rational matrix function with constant signature. Explicit formulas for these J-spectral factors are given in terms of a solution of a particular algebraic Riccati equation. Also, we discuss the common zero structure of rational matrix functions that arise from the analysis of nonsquare J-spectral factors. This zero structure is obtained in terms of the kernel of a generalized Bezoutian.