49Kxx Necessary conditions and sufficient conditions for optimality

49K05  Free problems in one independent variable
49K10  Free problems in two or more independent variables
49K15  Problems involving ordinary differential equations
49K20  Problems involving partial differential equations
49K22  Problems involving integral equations
49K24  Problems involving differential inclusions
49K25  Problems involving equations with retarded arguments, See
               also {34K35}
49K27  Problems in abstract spaces [See 90C48, 93C25]
49K30  Optimal solutions belonging to restricted classes
49K35  Minimax problems
49K40  Sensitivity of optimal solutions in the presence of
               perturbations
49K45  Problems involving randomness, See also {93E20}
49K99  None of the above but in this section