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JOURNALS // Izvestiya Vysshikh Uchebnykh Zavedenii. Matematika // Archive

Izv. Vyssh. Uchebn. Zaved. Mat., 2022 Number 12, Pages 34–56 (Mi ivm9835)

This article is cited in 2 papers

Stability criterion for linear differential equations with a delayed argument

S. A. Gusarenko

Perm State National Research University, 7 Henkel str., Perm, 614068 Russia

Abstract: A semi-effective criterion for the stability of linear differential equations $\mathcal{L} x=f$ with retarded argument is proposed, the general solution of which is represented by the Cauchy formula
$$ x(t)=C(t,a)x(a)+\int\limits_a^tC(t,s) f(s) ds. $$
The Cauchy function satisfies the integral identity
$$ C(t,s) = U(t,s)U(s,s)^{-1} - \int\limits_s^tC(t,\varsigma)\mathcal{L}_s U(\cdot, s)(\varsigma)U(s,s)^{-1} d\varsigma, $$
where $\mathcal{L}_s$ is the contraction of the operator $\mathcal{L}$ by the interval $[s,\infty)$. Choosing the function $U$ so that the function is $\mathcal{L}_s U(\cdot, s) U(s,s)^{-1}$ is small enough, it is possible to obtain estimates of the Cauchy function $C(t,s)$, which guarantee the stability of the differential equation.

Keywords: stability of differential equations with a delayed argument, stability criterion of differential equations, signs of stability of differential equations, Cauchy function, Cauchy formula.

UDC: 517.929

Received: 05.03.2022
Revised: 05.03.2022
Accepted: 29.06.2022

DOI: 10.26907/0021-3446-2022-12-34-56


 English version:
Russian Mathematics (Izvestiya VUZ. Matematika), 2022, 66:12, 33–52


© Steklov Math. Inst. of RAS, 2026