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 linear polynomial interpretations on N: first_A(x1,x2) = x1 + x2 + 3 first#_A(x1,x2) = x2 + 4 0_A = 1 0#_A = 1 nil_A = 0 nil#_A = 0 s_A(x1) = x1 s#_A(x1) = 1 cons_A(x1,x2) = x2 cons#_A(x1,x2) = 3 n__first_A(x1,x2) = x1 + x2 + 3 n__first#_A(x1,x2) = x2 + 3 activate_A(x1) = x1 activate#_A(x1) = x1 + 2 from_A(x1) = x1 + 3 from#_A(x1) = 4 n__from_A(x1) = x1 + 3 n__from#_A(x1) = 1 n__s_A(x1) = x1 n__s#_A(x1) = 0 precedence: first = 0 > nil = cons = n__first > activate > from > n__from = n__s > s