YES (VAR x0 x) (RULES a(a(a(b(x0)))) -> a(b(a(a(x0)))) a(b(a(a(b(x))))) -> a(x) ) (COMMENT Termination is shown by EKBO with interpretations on natural numbers a_A(x1) = 0 b_A(x1) = 1 weights w0 = 1 w(a) = 1 w(b) = 1 and precedence: a > b )