MAYBE
0.08/0.19	MAYBE
0.08/0.19	
0.08/0.19	Problem:
0.08/0.19	 active(first(0(),X)) -> mark(nil())
0.08/0.19	 active(first(s(X),cons(Y,Z))) -> mark(cons(Y,first(X,Z)))
0.08/0.19	 active(from(X)) -> mark(cons(X,from(s(X))))
0.08/0.19	 active(first(X1,X2)) -> first(active(X1),X2)
0.08/0.19	 active(first(X1,X2)) -> first(X1,active(X2))
0.08/0.19	 active(s(X)) -> s(active(X))
0.08/0.19	 active(cons(X1,X2)) -> cons(active(X1),X2)
0.08/0.19	 active(from(X)) -> from(active(X))
0.08/0.19	 first(mark(X1),X2) -> mark(first(X1,X2))
0.08/0.19	 first(X1,mark(X2)) -> mark(first(X1,X2))
0.08/0.19	 s(mark(X)) -> mark(s(X))
0.08/0.19	 cons(mark(X1),X2) -> mark(cons(X1,X2))
0.08/0.19	 from(mark(X)) -> mark(from(X))
0.08/0.19	 proper(first(X1,X2)) -> first(proper(X1),proper(X2))
0.08/0.19	 proper(0()) -> ok(0())
0.08/0.19	 proper(nil()) -> ok(nil())
0.08/0.19	 proper(s(X)) -> s(proper(X))
0.08/0.19	 proper(cons(X1,X2)) -> cons(proper(X1),proper(X2))
0.08/0.19	 proper(from(X)) -> from(proper(X))
0.08/0.19	 first(ok(X1),ok(X2)) -> ok(first(X1,X2))
0.08/0.19	 s(ok(X)) -> ok(s(X))
0.08/0.19	 cons(ok(X1),ok(X2)) -> ok(cons(X1,X2))
0.08/0.19	 from(ok(X)) -> ok(from(X))
0.08/0.19	 top(mark(X)) -> top(proper(X))
0.08/0.19	 top(ok(X)) -> top(active(X))
0.08/0.19	
0.08/0.19	Proof:
0.08/0.19	 Open
0.17/0.20	EOF