Hamiltonian Structures of Periodic Differential Equations with Even-Order Derivatives
摘要
This paper investigates the construction of an equivalent quasi-Hamiltonian system for a linear differential equation with periodic coefficients that contains only even-order derivatives and depends on a small parameter. We develop an approach based on transforming the unperturbed equation into an equivalent Hamiltonian system in normal form. It is shown that that the corresponding linear non-degenerate transformation provides a solution to the main problem. The obtained results are extended to an analogous problem for a linear periodic system with a small parameter, where the unperturbed system is defined by a Frobenius matrix. We discuss applications of these results to stability theory problems for solutions of differential equations in critical cases.