set A := { "a", "b", "c", "d" }; param w[A] := <"a"> 5, <"b"> 3, <"c"> 2, <"d"> 7; param v[A] := <"a"> 7, <"b"> 3, <"c"> 4, <"d"> 6; var x[A] binary; maximize knapsack_value: sum <i> in A: v[i] * x[i]; subto weight_limit: sum <i> in A: w[i] * x[i] <= 10;