“…It is to be noted that, as in Runge-Kutta methods, y n+c i are evaluated by numerical formulae which satisfy the order conditions listed in [20,Appendix A]. Thus, the values x 1,n+c i , x 2,n+c i , x 1,n+c i , x 2,n+c i , x 1,n+c i , x 2,n+c i , λ n+c i at off-step points should not be projected onto the constraints manifold.…”