TY - JOUR AU - Choi, Woocheol AU - Choi, Young-Pil PY - 2022 TI - A sharp error analysis for the DG method of optimal control problems JO - AIMS Mathematics SP - 9117 EP - 9155 VL - 7 IS - 5 AB - In this paper, we are concerned with a nonlinear optimal control problem of ordinary differential equations. We consider a discretization of the problem with the discontinuous Galerkin method with arbitrary order r ∈ N ∪ { 0 }. Under suitable regularity assumptions on the cost functional and solutions of the state equations, we first show the existence of a local solution to the discretized problem. We then provide sharp estimates for the L 2 -error of the approximate solutions. The convergence rate of the error depends on the regularity of the optimal solution u ¯ and its adjoint state with the degree of piecewise polynomials. Numerical experiments are presented supporting the theoretical results. UR - https://doi.org/10.3934/math.2022506 DO - 10.3934/math.2022506