Abstract:
We consider the Cauchy problem for the implicit differential equation of order nn g(t,x,˙x,…,x(n))=0,t∈[0,T],x(0)=A.g(t,x,˙x,…,x(n))=0,t∈[0,T],x(0)=A.
It is assumed that A=(A0,…,An−1)∈Rn, the function g:[0,T]×Rn+1→R is measurable with respect to the first argument t∈[0,T], and for a fixed t, the function g(t,⋅):Rn+1→R is right continuous and monotone in each of the first n arguments, and is continuous in the last n+1-th argument. It is also assumed that for some sufficiently smooth functions η,ν, there hold the inequalities
ν(i)(0)≥Ai≥η(i)(0),i=¯0,n−1,ν(n)(t)≥η(n)(t),t∈[0,T];g(t,ν(t),˙ν(t),…,ν(n)(t))≥0,g(t,η(t),˙η(t),…,η(n)(t))≤0,t∈[0,T].
Sufficient conditions for the solvability of the Cauchy problem are derived as well as estimates of its solutions. Moreover, it is shown that under the listed conditions, the set of solutions satisfying the inequalities ν(n)(t)≤x(n)(t)≤ν(n)(t) is not empty and contains solutions with the largest and the smallest n-th derivative. This statement is similar to the classical Chaplygin theorem on differential inequality. The proof method uses results on the solvability of equations in partially ordered spaces. Examples of applying the results obtained to the study of second-order implicit differential equations are given.
Keywords:
implicit differential equation of order n, largest and smallest solutions, estimates of solutions, Chaplygin's theorem on differential inequality.
Received: 15.06.2021
Document Type:
Article
UDC:517.922, 517.927.4
Language: Russian
Citation:
S. Benarab, “On Chaplygin's theorem for an implicit differential equation of order n”, Russian Universities Reports. Mathematics, 26:135 (2021), 225–233
\Bibitem{Ben21}
\by S.~Benarab
\paper On Chaplygin's theorem for an implicit differential equation of order~$n$
\jour Russian Universities Reports. Mathematics
\yr 2021
\vol 26
\issue 135
\pages 225--233
\mathnet{http://mi.mathnet.ru/vtamu227}
\crossref{https://doi.org/10.20310/2686-9667-2021-26-135-225-233}
Linking options:
https://www.mathnet.ru/eng/vtamu227
https://www.mathnet.ru/eng/vtamu/v26/i135/p225
This publication is cited in the following 4 articles:
A. A. Bazulkina, L. I. Rodina, “Teorema sravneniya dlya sistem differentsialnykh uravnenii i ee primenenie dlya otsenki srednei vremennoi vygody ot sbora resursa”, Izv. IMI UdGU, 63 (2024), 3–17
E. S. Zhukovskiy, I. D. Serova, “On a Control Problem for a System of Implicit Differential Equations”, Differentsialnye uravneniya, 59:9 (2023), 1283
Jervin Zen Lobo, Sanket Tikare, Mahammad Khuddush, “Chaplygin's method for second-order neutral differential equations with piecewise constant deviating arguments”, J Anal, 2023
S. Benarab, E. A. Panasenko, “Ob odnom vklyuchenii s otobrazheniem, deistvuyuschim iz chastichno uporyadochennogo prostranstva v mnozhestvo s refleksivnym binarnym otnosheniem”, Vestn. Udmurtsk. un-ta. Matem. Mekh. Kompyut. nauki, 32:3 (2022), 361–382