MAYBE
0.08/0.18	MAYBE
0.08/0.18	
0.08/0.18	Problem:
0.08/0.18	 active(f(b(),X,c())) -> mark(f(X,c(),X))
0.08/0.18	 active(c()) -> mark(b())
0.08/0.18	 active(f(X1,X2,X3)) -> f(X1,active(X2),X3)
0.08/0.18	 f(X1,mark(X2),X3) -> mark(f(X1,X2,X3))
0.08/0.18	 proper(f(X1,X2,X3)) -> f(proper(X1),proper(X2),proper(X3))
0.08/0.18	 proper(b()) -> ok(b())
0.08/0.18	 proper(c()) -> ok(c())
0.08/0.18	 f(ok(X1),ok(X2),ok(X3)) -> ok(f(X1,X2,X3))
0.08/0.18	 top(mark(X)) -> top(proper(X))
0.08/0.18	 top(ok(X)) -> top(active(X))
0.08/0.18	
0.08/0.18	Proof:
0.08/0.18	 Open
0.08/0.19	EOF