$\K$-Lorentzian and $\K$-CLC Polynomials in Stability Analysis

Abstract

We study the class of $\K$-Lorentzian polynomials, a generalization of the distinguished class of Lorentzian polynomials. As shown in \cite{GPlorentzian}, the set of $\K$-Lorentzian polynomials is equivalent to the set of $\K$-completely log-concave (aka $\K$-CLC) forms. Throughout this paper, we interchangeably use the terms $\K$-Lorentzian polynomials for the homogeneous setting and $\K$-CLC polynomials for the non-homogeneous setting. By introducing an alternative definition of $\K$-CLC polynomials through univariate restrictions, we establish that any strictly $\K$-CLC polynomial of degree $d\le 4$ is Hurwitz-stable polynomial over $\K$. Additionally, we characterize the conditions under which a strictly $\K$-CLC of degree $d\ge 5$ is Hurwitz-stable over $\K$. Furthermore, we associate the largest possible proper cone, denoted by $\K(f,v)$, with a given $\K$-Lorentzian polynomial $f$ in the direction $v \in \inter \K$. Finally, we investigate applications of $\K$-CLC polynomials in the stability analysis of evolution variational inequalities (EVI) dynamical systems governed by differential equations and inequality constraints.