196.48/50.30	MAYBE
196.48/50.30	
196.48/50.30	Problem:
196.48/50.30	 b(c(x1)) -> d(c(x1))
196.48/50.30	 b(d(x1)) -> d(b(x1))
196.48/50.30	 a(d(x1)) -> a(b(b(x1)))
196.48/50.30	
196.48/50.30	Proof:
196.48/50.30	 Open
196.84/50.31	EOF