MAYBE
47.48/13.58	MAYBE
47.48/13.58	
47.48/13.58	Problem:
47.48/13.58	 a(d(x1)) -> d(b(x1))
47.48/13.58	 a(x1) -> b(b(b(x1)))
47.48/13.58	 d(x1) -> x1
47.48/13.58	 a(x1) -> x1
47.48/13.58	 b(d(b(x1))) -> a(d(x1))
47.48/13.58	 b(c(x1)) -> c(d(d(x1)))
47.48/13.58	 a(c(x1)) -> b(b(c(d(x1))))
47.48/13.58	
47.48/13.58	Proof:
47.48/13.58	 Open
47.48/13.58	EOF