MAYBE
0.07/0.18	MAYBE
0.07/0.18	
0.07/0.18	Problem:
0.07/0.18	 numbers() -> d(0())
0.07/0.18	 d(x) -> if(le(x,nr()),x)
0.07/0.18	 if(true(),x) -> cons(x,d(s(x)))
0.07/0.18	 if(false(),x) -> nil()
0.07/0.18	 le(0(),y) -> true()
0.07/0.18	 le(s(x),0()) -> false()
0.07/0.18	 le(s(x),s(y)) -> le(x,y)
0.07/0.18	 nr() -> ack(s(s(s(s(s(s(0())))))),0())
0.07/0.18	 ack(0(),x) -> s(x)
0.07/0.18	 ack(s(x),0()) -> ack(x,s(0()))
0.07/0.18	 ack(s(x),s(y)) -> ack(x,ack(s(x),y))
0.07/0.18	
0.07/0.18	Proof:
0.07/0.18	 Open
0.07/0.19	EOF