YES TRS: first(0(),X) -> nil() first(s(X),cons(Y,Z)) -> cons(Y,n__first(X,activate(Z))) from(X) -> cons(X,n__from(n__s(X))) first(X1,X2) -> n__first(X1,X2) from(X) -> n__from(X) s(X) -> n__s(X) activate(n__first(X1,X2)) -> first(activate(X1),activate(X2)) activate(n__from(X)) -> from(activate(X)) activate(n__s(X)) -> s(activate(X)) activate(X) -> X max/plus interpretations on N: first_A(x1,x2) = max{14, 4 + x1, 8 + x2} first#_A(x1,x2) = max{14, 4 + x1, 8 + x2} 0_A = 16 0#_A = 16 nil_A = 15 nil#_A = 15 s_A(x1) = max{11, x1} s#_A(x1) = max{11, x1} cons_A(x1,x2) = max{7, 7 + x1, x2} cons#_A(x1,x2) = max{7, 7 + x1, x2} n__first_A(x1,x2) = max{14, 4 + x1, 8 + x2} n__first#_A(x1,x2) = max{14, 4 + x1, 8 + x2} activate_A(x1) = max{5, x1} activate#_A(x1) = max{5, x1} from_A(x1) = max{23, 12 + x1} from#_A(x1) = max{23, 12 + x1} n__from_A(x1) = max{23, 12 + x1} n__from#_A(x1) = max{23, 12 + x1} n__s_A(x1) = max{11, x1} n__s#_A(x1) = max{11, x1} precedence: 0 > nil = activate > first = s = from > cons = n__first = n__from = n__s