Insights in Characterizing Asymptotic Behavior for Quasipolynomials with Two Delays

International audience; This paper proposes an analytical method to characterize the behavior of multiple critical roots of a retarded system with two delays. Expressing locally the related characteristic function, as a Weierstrass polynomial, we derive several results to analyze the stability behavior of such characteristic roots with respect to small variations on the delay parameters. The proposed results are illustrated by considering several numerical examples.