YES O(n^3) TRS: { filter(cons(X), 0(), M) -> cons(0()), filter(cons(X), s(N), M) -> cons(X), sieve(cons(0())) -> cons(0()), sieve(cons(s(N))) -> cons(s(N)), nats(N) -> cons(N), zprimes() -> sieve(nats(s(s(0())))) } DUP: We consider a non-duplicating system. Trs: { filter(cons(X), 0(), M) -> cons(0()), filter(cons(X), s(N), M) -> cons(X), sieve(cons(0())) -> cons(0()), sieve(cons(s(N))) -> cons(s(N)), nats(N) -> cons(N), zprimes() -> sieve(nats(s(s(0())))) } Matrix Interpretation: Interpretation class: triangular [3] [zprimes] = [1] [1] [X2] [1 2 2][X2] [1] [nats]([X1]) = [0 0 0][X1] + [2] [X0] [0 0 0][X0] [0] [X2] [1 0 0][X2] [1] [sieve]([X1]) = [0 0 0][X1] + [0] [X0] [0 0 0][X0] [0] [X2] [1 0 0][X2] [0] [s]([X1]) = [0 0 0][X1] + [0] [X0] [0 0 0][X0] [0] [X8] [X5] [X2] [1 0 0][X8] [1 0 0][X5] [1 0 2][X2] [2] [filter]([X7], [X4], [X1]) = [0 0 0][X7] + [0 0 0][X4] + [0 0 2][X1] + [0] [X6] [X3] [X0] [0 0 0][X6] [0 0 0][X3] [0 0 0][X0] [2] [0] [0] = [0] [0] [X2] [1 0 0][X2] [0] [cons]([X1]) = [0 0 0][X1] + [0] [X0] [0 0 0][X0] [0] Qed