On the stability of a nonlinear nonautonomous scalar equation with variable delay
- Authors: Khusanov J.K.1, Azizbeck E. Kaxxorov A.E.2
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Affiliations:
- Sambhram University
- Academic lyceum of Tashkent State Technical University named after I.Karimov
- Issue: Vol 25, No 4 (2023)
- Pages: 299-312
- Section: Mathematics
- Submitted: 22.12.2025
- Accepted: 22.12.2025
- Published: 24.12.2025
- URL: https://journal-vniispk.ru/2079-6900/article/view/360848
- DOI: https://doi.org/10.15507/2079-6900.25.202304.299-312
- ID: 360848
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Abstract
The stability problem of a scalar functional differential equation is a classical one. It has been most fully studied for linear equations. Modern research on modeling biological, infectious and other processes leads to the need to determine the qualitative properties of the solutions for more general equations. In this paper we study the stability and the global limit behavior of solutions to a nonlinear one-dimensional (scalar) equation with variable delay with unbounded and bounded right-hand sides. In particular, our research is reduced to a problem on the stability of a non-stationary solution of a nonlinear scalar Lotka-Volterra-type equation, on the stabilization and control of a non-stationary process described by such an equation. The problem posed is considered depending on the delay behavior: is it a bounded differentiable function or a continuous and bounded one. The study is based on the application of the Lyapunov-Krasovsky functionals method as well as the corresponding theorems on the stability of non-autonomous functional differential equations of retarded type with finite delay. Sufficient conditions are derived for uniform asymptotic stability of the zero solution, including global stability, for every continuous initial function. Using the theorem proven by one of the co-authors on the limiting behavior of solutions to a non-autonomous functional differential equation based on the Lyapunov functional with a semidefinite derivative, the properties of the solutions’ attraction to the set of equilibrium states of the equation under study are obtained. In addition, illustrative examples are provided.
About the authors
Jumanazar Kh. Khusanov
Sambhram University
Email: d.khusanov1952@mail.ru
ORCID iD: 0000-0001-9444-9324
Dr. Sc. (Physics and Mathematics), Professor
Uzbekistan, 3, H. Nosirov Street, Jizzakh 130100, UzbekistanAzizbeck E. Azizbeck E. Kaxxorov
Academic lyceum of Tashkent State Technical University named after I.Karimov
Author for correspondence.
Email: azizqahhorov@gmail.com
ORCID iD: 0000-0001-5723-8640
Graduate Student
Uzbekistan, 2, University street, Tashkent 100095, UzbekistanReferences
- A. D. Myshkis, Linear differential equations with delayed argument, GITTL Publ., Moscow, Leningrad, 1951 (In Russ.), 254 p.
- R. Bellman, K. L. Cooke, Differential-difference equations, Academic Press, New York, 1963, 478 p.
- N. N. Krasovsky, Stability of motion, Stanford University Press, Stanford, 1963, 194 p.
- J. K. Hale, Theory of functional differential equations, Springer, New York, 1971 DOI:
- https://doi.org/10.1007/978-1-4612-9892-2, 366 p.
- T. Amemiya, "On the delay-independent stability of a delayed differential equation of 1st order", J. Math. Anal. and Appl., 142:1 (1989), 13—25. DOI: https://doi.org/10.1016/0022-247X(89)90159-5
- T. Krisztin, "On stability properties for one-dimensional functional-differential equations", Funkcial. Ekvac., 34:2 (1991), 241–256.
- V. V. Malygina, K. M. Chudinov, "Stability of solutions to differential equations with several variable delays. III", Russian Mathematics (Izvestiya VUZ. Matematika), 57:8 (2013), 37–48. DOI: https://doi.org/10.3103/S1066369X13080057
- L. Berezansky, E. Braverman, "Stability conditions for scalar delay differential equations with a non-delay term", Applied Mathematics and Computation, 250:5 (2015), 157–164. DOI: https://doi.org/10.1016/j.amc.2014.10.088
- A. Egorov, "On the stability analysis of equations with bounded timevarying delay", J. IFAC-Papers on Line, 52:18 (2019), 85—90. DOI: https://doi.org/10.1016/j.ifacol.2019.12.211
- L. Berezansky, E. Braverman, "On exponential stability of linear delay equations with oscillatory coefficients and kernels", Differential and Integral Equations, 35:9-10 (2022), 559–580. DOI: https://doi.org/10.48550/arXiv.2208.09018
- T. Yoneyama, "Uniform stability for one dimensional delay-differential equations with dominant delayed term", Tohoku Math J., 41:2 (1989), 217–236.
- T. A. Burton, "Uniform asymptotic stability in functional differential equations", Proceedings of the American Mathematical Society, 68:2 (1978), 195—199. DOI: https://doi.org/10.2307/2041771
- T. Burton, L. Hatvani, "Stability theorems for nonautonomous functional differential equations by Liapunov functionals", Tohoku Mathematical Journal, Second Series, 41:1 (1989), 65—104. DOI: https://doi.org/10.2748/tmj/1178227868
- L. Hatvani, "On the asymptotic stability for nonautonomous functional differential equations by Lyapunov functionals", Transactions of the American Mathematical Society, 354:9 (2002), 3555–3571.
- N. V. Pertsev, B. Yu. Pichugin, A. N. Pichugina, "Investigation of solutions to one family of mathematical models of living systems", Russian Math. (Iz. VUZ), 61:9 (2017), 54–68.
- N. V. Pertsev, "Application of differential equations with variable delay in the compartmental models of living systems", Sib. Zh. Ind. Mat., 24:3 (2021), 55—73. DOI: https://doi.org/10.33048/SIBJIM.2021.24.305
- J. K. Khusanov, A. E. Kaxxorov, "On the stability of Lotka-Volterra model with a delay", Zhurnal Srednevolzhskogo matematicheskogo obshchestva, 24:2 (2022), 175–184.
- DOI: https://doi.org/10.15507/2079-6900.24.202202.175-184
- A. V. Ekimov, A. P. Zhabko, P. V. Yakovlev, "The stability of differential-difference systems with linearly increasing delay. II. Systems with additive right side", Bulletin of St. Petersburg University. Applied Mathematics. Computer science. Management processes, 19:1 (2023), 4—9. DOI: https://doi.org/10.21638/11701/spbul0.2023.101
- A. S. Andreev, D. Kh. Khusanov, "On the method of Lyapunov functionals in the problem of asymptotic stability and instability", Differential Equations, 34:7 (1998), 876–885.
- D. Kh. Khusanov, On the constructive and qualitative theory of functional differential equations, Tashkent: FAN. AN RUz, 2002 (In Russ.), 256 p.
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