YES O(n^3) TRS: { g(a()) -> g(b()), b() -> f(a(), a()), f(a(), a()) -> g(d())} DUP: We consider a non-duplicating system. Trs: { g(a()) -> g(b()), b() -> f(a(), a()), f(a(), a()) -> g(d())} Matrix Interpretation: Interpretation class: triangular [1] [d] = [0] [0] [X5] [X2] [1 0 0][X5] [1 0 0][X2] [2] [f]([X4], [X1]) = [0 0 0][X4] + [0 0 0][X1] + [0] [X3] [X0] [0 0 0][X3] [0 0 0][X0] [0] [0] [a] = [0] [2] [3] [b] = [0] [0] [X2] [1 0 2][X2] [0] [g]([X1]) = [0 0 0][X1] + [0] [X0] [0 0 0][X0] [0] Qed