Oleh Perehuda, Natalya Denysenko, Svitlana Kushnirenko

Approximation of Delay Functional-Differential Equations by Delay-Free Equations in Banach Spaces

abstract:
This paper develops a comprehensive approximation framework for functional-differential equations with delays in infinite-dimensional Banach spaces. Particular attention is devoted to the replacement of the original delayed system by an associated evolutionary system of delay-free differential equations. Such an approach not only simplifies the analytical treatment of delayed dynamics, but also provides a foundation for numerical implementations and further qualitative analysis of infinite-dimensional control systems. The proposed approach involves partitioning the delay interval into subintervals and constructing the corresponding system of equations that approximates the behavior of the original system. The main result of the study shows that, as the mesh size of the partition tends to zero, the distance between the solutions of the delayed equation and those of the delay-free system also tends to zero.

Mathematics Subject Classification: 35R10, 35R60, 60H15

Key words and phrases: Mild solution, generator, semigroup, approximation