YES O(n^2) 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 [X3] [X1] [1 0][X3] [1 1][X1] [0] [f]([X2], [X0]) = [0 0][X2] + [0 0][X0] + [0] [1] [b] = [1] [1] [a] = [1] [0] [c] = [0] [X1] [1 1][X1] [0] [g]([X0]) = [0 1][X0] + [0] Qed