E. Casas et al., Second order sufficient optimality conditions for some state-constrained control problems of semilinear elliptic equations, SIAM J CON, 38(5), 2000, pp. 1369-1391
This paper deals with a class of optimal control problems governed by ellip
tic equations with nonlinear boundary condition. The case of boundary contr
ol is studied. Pointwise constraints on the control and certain equality an
d set-constraints on the state are considered. Second order sufficient cond
itions for local optimality of controls are established.