MAYBE
0.09/0.17	MAYBE
0.09/0.17	
0.09/0.17	Problem:
0.09/0.17	 a__from(X) -> cons(mark(X),from(s(X)))
0.09/0.17	 a__sel(0(),cons(X,Y)) -> mark(X)
0.09/0.17	 a__sel(s(X),cons(Y,Z)) -> a__sel(mark(X),mark(Z))
0.09/0.17	 mark(from(X)) -> a__from(mark(X))
0.09/0.17	 mark(sel(X1,X2)) -> a__sel(mark(X1),mark(X2))
0.09/0.17	 mark(cons(X1,X2)) -> cons(mark(X1),X2)
0.09/0.17	 mark(s(X)) -> s(mark(X))
0.09/0.17	 mark(0()) -> 0()
0.09/0.17	 a__from(X) -> from(X)
0.09/0.17	 a__sel(X1,X2) -> sel(X1,X2)
0.09/0.17	
0.09/0.17	Proof:
0.09/0.17	 Open
0.09/0.18	EOF