Asymptotic integration of a nonhomogeneous differential equation with integrable coefficients
We study the asymptotic behavior of the solutions of a differential equation with unbounded delay. The results presented are based on the first Lyapunov method, which is often used to construct solutions of ordinary differential equations in the form of power series. This technique cannot be applied to delayed equations and hence we express the solution as an asymptotic expansion. The existence of a solution is proved by the retract method.
In this paper new generalized notions are defined: -boundedness and -asymptotic equivalence, where is a complex continuous nonsingular matrix. The -asymptotic equivalence of linear differential systems and is proved when the fundamental matrix of is -bounded.
Asymptotic representations of some classes of solutions of nonautonomous ordinary differential -th order equations which somewhat are close to linear equations are established.