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