YES O(n^2) TRS: {f(f(a())) -> f(g())} Natural interpretation: Strict: {f(f(a())) -> f(g())} Weak: {} Interpretation class: deltarestricted [a](delta) = + 0 + 1*delta [g](delta) = + 0 + 0*delta [f](delta, X0) = + 0*X0 + 0 + 1*X0*delta + 0*delta f_tau_1(delta) = delta/(0 + 1 * delta) Qed