Il’ichev, V. G. Stable systems with two delays. (English. Russian original) Zbl 0906.93049 J. Comput. Syst. Sci. Int. 36, No. 2, 190-196 (1997); translation from Izv. Akad. Nauk, Teor. Sist. Upr. 1997, No. 2, 34-40 (1997). The paper is devoted to second-order linear autonomous equations with two constant delays. The corresponding quasipolynomial \[ z^2+z+1=c [\exp(-a_1 z)+ \exp(-z a_2)] \] with constants \(c, a_1>0, a_2>0\) is investigated. The possible directions of stable rays are defined. In addition, it is proved that the set of stable rays is finite. Reviewer: Michael I.Gil’(Beer-Sheva) MSC: 93D20 Asymptotic stability in control theory 34K20 Stability theory of functional-differential equations 93C80 Frequency-response methods in control theory Keywords:linear retarded equations; stability; quasipolynomial; stable rays PDFBibTeX XMLCite \textit{V. G. Il'ichev}, J. Comput. Syst. Sci. Int. 36, No. 2, 190--196 (1997; Zbl 0906.93049); translation from Izv. Akad. Nauk, Teor. Sist. Upr. 1997, No. 2, 34--40 (1997)