YES weighted path orer with linear polynomial on natural numbers: f_A(x1) = 3 g_A(x1) = 2 a_A = 1 b_A = 0 F_A(x1) = x1 precedence: a > F > b > f > g status: f: [] g: [] a: [] b: [] F: [] the condition F(a()) ->> F(g(a())) is unsatisfiable for all substitutions.