Convergence of the method of trigonometric collocation for nonlinear periodic systems of differential equations with retarded argument (Q798497)

For a nonlinear periodic system with constant delay it is proved that if an isolated periodic solution exists (the corresponding variational system has no nontrivial periodic solution) then the equations defining the collocation approximations with trigonometric polynomials have solutions and the collocation approximations converge uniformly to the solution (estimates are also obtained).