On the Rellich eigendecomposition of para-Hermitian matrices and the sign characteristics of $\ast$-palindromic matrix polynomials

Giovanni Barbarino, Vanni Noferini

We study the eigendecompositions of para-Hermitian matrices $H(z)$, that is, matrix-valued functions that are analytic and Hermitian on the unit circle $S^1\subset \mathbb{C}$. In…