MAYBE
0.08/0.18	MAYBE
0.08/0.18	
0.08/0.18	Problem:
0.08/0.18	 a__and(true(),X) -> mark(X)
0.08/0.18	 a__and(false(),Y) -> false()
0.08/0.18	 a__if(true(),X,Y) -> mark(X)
0.08/0.18	 a__if(false(),X,Y) -> mark(Y)
0.08/0.18	 a__add(0(),X) -> mark(X)
0.08/0.18	 a__add(s(X),Y) -> s(add(X,Y))
0.08/0.18	 a__first(0(),X) -> nil()
0.08/0.18	 a__first(s(X),cons(Y,Z)) -> cons(Y,first(X,Z))
0.08/0.18	 a__from(X) -> cons(X,from(s(X)))
0.08/0.18	 mark(and(X1,X2)) -> a__and(mark(X1),X2)
0.08/0.18	 mark(if(X1,X2,X3)) -> a__if(mark(X1),X2,X3)
0.08/0.18	 mark(add(X1,X2)) -> a__add(mark(X1),X2)
0.08/0.18	 mark(first(X1,X2)) -> a__first(mark(X1),mark(X2))
0.08/0.18	 mark(from(X)) -> a__from(X)
0.08/0.18	 mark(true()) -> true()
0.08/0.18	 mark(false()) -> false()
0.08/0.18	 mark(0()) -> 0()
0.08/0.18	 mark(s(X)) -> s(X)
0.08/0.18	 mark(nil()) -> nil()
0.08/0.18	 mark(cons(X1,X2)) -> cons(X1,X2)
0.08/0.18	 a__and(X1,X2) -> and(X1,X2)
0.08/0.18	 a__if(X1,X2,X3) -> if(X1,X2,X3)
0.08/0.18	 a__add(X1,X2) -> add(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
0.08/0.19	EOF