MAYBE
29.07/10.18	MAYBE
29.07/10.18	
29.07/10.18	Problem:
29.07/10.18	 a(x1) -> x1
29.07/10.18	 a(a(x1)) -> b(c(x1))
29.07/10.18	 b(x1) -> x1
29.07/10.18	 c(x1) -> x1
29.07/10.18	 c(b(x1)) -> a(b(c(x1)))
29.07/10.18	
29.07/10.18	Proof:
29.07/10.18	 Open
29.07/10.19	EOF