MAYBE
0.09/0.18	MAYBE
0.09/0.18	
0.09/0.18	Problem:
0.09/0.18	 +(0(),y) -> y
0.09/0.18	 +(s(x),y) -> s(+(x,y))
0.09/0.18	 ++(nil(),ys) -> ys
0.09/0.18	 ++(:(x,xs),ys) -> :(x,++(xs,ys))
0.09/0.18	 sum(:(x,nil())) -> :(x,nil())
0.09/0.18	 sum(:(x,:(y,xs))) -> sum(:(+(x,y),xs))
0.09/0.18	 sum(++(xs,:(x,:(y,ys)))) -> sum(++(xs,sum(:(x,:(y,ys)))))
0.09/0.18	 -(x,0()) -> x
0.09/0.18	 -(0(),s(y)) -> 0()
0.09/0.18	 -(s(x),s(y)) -> -(x,y)
0.09/0.18	 quot(0(),s(y)) -> 0()
0.09/0.18	 quot(s(x),s(y)) -> s(quot(-(x,y),s(y)))
0.09/0.18	 length(nil()) -> 0()
0.09/0.18	 length(:(x,xs)) -> s(length(xs))
0.09/0.18	 hd(:(x,xs)) -> x
0.09/0.18	 avg(xs) -> quot(hd(sum(xs)),length(xs))
0.09/0.18	
0.09/0.18	Proof:
0.09/0.18	 Open
0.09/0.18	EOF