YES TRS: f(f(X)) -> f(a(b(f(X)))) f(a(g(X))) -> b(X) b(X) -> a(X) linear polynomial interpretations on N: f_A(x1) = 2 f#_A(x1) = x1 + 1 a_A(x1) = 1 a#_A(x1) = 0 b_A(x1) = 1 b#_A(x1) = 1 g_A(x1) = x1 + 1 g#_A(x1) = 2 precedence: f = g > b > a