Tamaz Tadumadze and Nika Gorgodze

Variation Formulas of a Solution and Initial Data Optimization Problems for Quasi-Linear Neutral Functional Differential Equations with Discontinuous Initial Condition

abstract:
For the quasi-linear neutral functional differential equation the continuous dependence of a solution of the Cauchy problem on the initial data and on the nonlinear term in the right-hand side of that equation is investigated, where the perturbation nonlinear term in the right-hand side and initial data are small in the integral and standard sense, respectively. Variation formulas of a solution are derived, in which the effect of perturbations of the initial moment and the delay function, and also that of the discontinuous initial condition are detected. For initial data optimization problems the necessary conditions of optimality are
obtained. The existence theorem for optimal initial data is proved.

Mathematics Subject Classification: 34K38, 34K40, 34K27, 49J21, 49K21

Key words and phrases: Quasi-linear neutral functional differential equation, continuous dependence of solution, variation formula of solution, effect of initial moment perturbation, effect of a discontinuous initial condition, effect of delay function perturbation, initial data optimization problem, necessary conditions of optimality, existence of optimal initial data