We study the reachability problem for queue automata and lossy queue automata. Concretely, we consider the set of queue contents which are forwards resp. backwards reachable from a given set of queue contents. Here, we prove the preservation of regularity if the queue automaton loops through some special sets of transformation sequences. This is a generalization of the results by Boigelot et al. and Abdulla et al. regarding queue automata looping through a single sequence of transformations. We also prove that our construction is possible in polynomial time.

中文翻译：

---

可靠有损队列自动机的可达性问题

我们研究队列自动机和有损队列自动机的可达性问题。具体来说，我们考虑转发和转发的队列内容集。从一组给定的队列内容向后可达。在这里，我们证明如果队列自动机循环通过一些特殊的转换序列集，则规则性的保持。这是 Boigelot 等人的结果的概括。和阿卜杜拉等人。关于队列自动机循环通过单个转换序列。我们还证明了我们的构造在多项式时间内是可能的。