YES O(n^4) TRS: { activate(X) -> X, and(tt(), X) -> activate(X), plus(N, 0()) -> N, plus(N, s(M)) -> s(plus(N, M)) } DUP: We consider a non-duplicating system. Trs: { activate(X) -> X, and(tt(), X) -> activate(X), plus(N, 0()) -> N, plus(N, s(M)) -> s(plus(N, M)) } Matrix Interpretation: Interpretation class: triangular [X3] [1 0 0 0][X3] [0] [X2] [0 0 0 0][X2] [0] [s]([X1]) = [0 0 0 0][X1] + [0] [X0] [0 0 0 1][X0] [1] [1] [0] [0] = [0] [1] [X7] [X3] [1 0 0 0][X7] [1 0 0 1][X3] [0] [X6] [X2] [0 1 1 1][X6] [0 0 0 0][X2] [0] [plus]([X5], [X1]) = [0 0 1 0][X5] + [0 0 0 0][X1] + [0] [X4] [X0] [0 0 0 1][X4] [0 0 0 1][X0] [0] [1] [0] [tt] = [0] [0] [X7] [X3] [1 0 0 0][X7] [1 0 0 1][X3] [1] [X6] [X2] [0 0 0 0][X6] [0 1 0 0][X2] [0] [and]([X5], [X1]) = [0 0 0 0][X5] + [0 0 1 0][X1] + [0] [X4] [X0] [0 0 0 0][X4] [0 0 0 1][X0] [0] [X3] [1 0 0 0][X3] [1] [X2] [0 1 0 0][X2] [0] [activate]([X1]) = [0 0 1 0][X1] + [0] [X0] [0 0 0 1][X0] [0] Qed