YES O(n^4) 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] [1] [X3] [1 0 0 1][X3] [1] [X2] [0 0 0 0][X2] [0] [s]([X1]) = [0 0 0 0][X1] + [0] [X0] [0 0 0 1][X0] [0] [X11] [X7] [X3] [1 0 0 0][X11] [1 0 0 1][X7] [1 0 0 0][X3] [0] [X10] [X6] [X2] [0 1 0 0][X10] [0 0 0 0][X6] [0 0 0 0][X2] [0] [p]([ X9], [X5], [X1]) = [0 0 1 0][X9] + [0 0 0 0][X5] + [0 0 0 0][X1] + [0] [ X8] [X4] [X0] [0 0 0 1][X8] [0 0 0 1][X4] [0 0 0 1][X0] [0] Qed