49Kxx Optimality conditions
 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
(2)
 49K21 Problems involving relations other than differential equations
 49K27 Problems in abstract spaces [See also 90C48, 93C25]
 49K30 Optimal solutions belonging to restricted classes

49K35 Minimax problems
(1)
 49K40 Sensitivity, stability, wellposedness [See also 90C31]
 49K45 Problems involving randomness [See also 93E20]
 49K99 None of the above, but in this section