YES O(n^3) TRS: {-(+(x, y), y) -> x, +(-(x, y), z) -> -(+(x, z), y)} DUP: We consider a non-duplicating system. Trs: {-(+(x, y), y) -> x, +(-(x, y), z) -> -(+(x, z), y)} Matrix Interpretation: Interpretation class: triangular [X5] [X2] [1 1 1][X5] [1 0 0][X2] [0] [+]([X4], [X1]) = [0 1 0][X4] + [0 0 0][X1] + [1] [X3] [X0] [0 0 1][X3] [0 0 0][X0] [0] [X5] [X2] [1 1 0][X5] [1 0 0][X2] [0] [-]([X4], [X1]) = [0 1 0][X4] + [0 0 0][X1] + [1] [X3] [X0] [0 0 1][X3] [0 0 0][X0] [1] Qed