MAYBE
0.18/0.20	MAYBE
0.18/0.20	
0.18/0.20	Problem:
0.18/0.20	 active(f(X)) -> mark(cons(X,f(g(X))))
0.18/0.20	 active(g(0())) -> mark(s(0()))
0.18/0.20	 active(g(s(X))) -> mark(s(s(g(X))))
0.18/0.20	 active(sel(0(),cons(X,Y))) -> mark(X)
0.18/0.20	 active(sel(s(X),cons(Y,Z))) -> mark(sel(X,Z))
0.18/0.20	 active(f(X)) -> f(active(X))
0.18/0.20	 active(cons(X1,X2)) -> cons(active(X1),X2)
0.18/0.20	 active(g(X)) -> g(active(X))
0.18/0.20	 active(s(X)) -> s(active(X))
0.18/0.20	 active(sel(X1,X2)) -> sel(active(X1),X2)
0.18/0.20	 active(sel(X1,X2)) -> sel(X1,active(X2))
0.18/0.20	 f(mark(X)) -> mark(f(X))
0.18/0.20	 cons(mark(X1),X2) -> mark(cons(X1,X2))
0.18/0.20	 g(mark(X)) -> mark(g(X))
0.18/0.20	 s(mark(X)) -> mark(s(X))
0.18/0.20	 sel(mark(X1),X2) -> mark(sel(X1,X2))
0.18/0.20	 sel(X1,mark(X2)) -> mark(sel(X1,X2))
0.18/0.20	 proper(f(X)) -> f(proper(X))
0.18/0.20	 proper(cons(X1,X2)) -> cons(proper(X1),proper(X2))
0.18/0.20	 proper(g(X)) -> g(proper(X))
0.18/0.20	 proper(0()) -> ok(0())
0.18/0.20	 proper(s(X)) -> s(proper(X))
0.18/0.20	 proper(sel(X1,X2)) -> sel(proper(X1),proper(X2))
0.18/0.20	 f(ok(X)) -> ok(f(X))
0.18/0.20	 cons(ok(X1),ok(X2)) -> ok(cons(X1,X2))
0.18/0.20	 g(ok(X)) -> ok(g(X))
0.18/0.20	 s(ok(X)) -> ok(s(X))
0.18/0.20	 sel(ok(X1),ok(X2)) -> ok(sel(X1,X2))
0.18/0.20	 top(mark(X)) -> top(proper(X))
0.18/0.20	 top(ok(X)) -> top(active(X))
0.18/0.20	
0.18/0.20	Proof:
0.18/0.20	 Open
0.18/0.20	EOF