MAYBE
0.08/0.18	MAYBE
0.08/0.18	
0.08/0.18	Problem:
0.08/0.18	 a__first(0(),X) -> nil()
0.08/0.18	 a__first(s(X),cons(Y,Z)) -> cons(mark(Y),first(X,Z))
0.08/0.18	 a__from(X) -> cons(mark(X),from(s(X)))
0.08/0.18	 mark(first(X1,X2)) -> a__first(mark(X1),mark(X2))
0.08/0.18	 mark(from(X)) -> a__from(mark(X))
0.08/0.18	 mark(0()) -> 0()
0.08/0.18	 mark(nil()) -> nil()
0.08/0.18	 mark(s(X)) -> s(mark(X))
0.08/0.18	 mark(cons(X1,X2)) -> cons(mark(X1),X2)
0.08/0.18	 a__first(X1,X2) -> first(X1,X2)
0.08/0.18	 a__from(X) -> from(X)
0.08/0.18	
0.08/0.18	Proof:
0.08/0.18	 Open
0.08/0.18	EOF