MAYBE
50.38/15.70	MAYBE
50.38/15.70	
50.38/15.70	Problem:
50.38/15.70	 a(a(x1)) -> x1
50.38/15.70	 a(b(x1)) -> x1
50.38/15.70	 a(b(b(x1))) -> b(b(a(b(a(x1)))))
50.38/15.70	
50.38/15.70	Proof:
50.38/15.70	 Open
50.38/15.70	EOF