489     optim
419     multi
416     object
259     function
173     pareto
167     machin
138     criteria
134     multiobject
111     learn
110     vector
103     minim
99      multipl
74      optimum
64      maximum
54      domin
51      minimum
43      conflict
33      multicriteria
31      criterion
27      optimis
20      nondomin
17      compromis
15      mcdm