YES O(n^5) TRS: { p(m, n, s(r)) -> p(m, r, n), p(m, s(n), 0()) -> p(0(), n, m), p(m, 0(), 0()) -> m } DUP: We consider a non-duplicating system. Trs: { p(m, n, s(r)) -> p(m, r, n), p(m, s(n), 0()) -> p(0(), n, m), p(m, 0(), 0()) -> m } Matrix Interpretation: Interpretation class: triangular [0] [0] [0] = [0] [0] [1] [X4] [1 0 0 0 1][X4] [1] [X3] [0 0 0 0 0][X3] [0] [s]([X2]) = [0 0 0 0 0][X2] + [0] [X1] [0 0 0 0 0][X1] [0] [X0] [0 0 0 0 1][X0] [0] [X14] [X9] [X4] [1 0 0 0 0][X14] [1 0 0 0 1][X9] [1 0 0 0 0][X4] [0] [X13] [X8] [X3] [0 1 0 0 0][X13] [0 0 0 0 0][X8] [0 0 0 0 0][X3] [0] [p]([X12], [X7], [X2]) = [0 0 1 0 0][X12] + [0 0 0 0 0][X7] + [0 0 0 0 0][X2] + [0] [X11] [X6] [X1] [0 0 0 1 0][X11] [0 0 0 0 0][X6] [0 0 0 0 0][X1] [0] [X10] [X5] [X0] [0 0 0 0 1][X10] [0 0 0 0 1][X5] [0 0 0 0 1][X0] [0] Qed