Abstract
We introduce asynchronous variants of the parallel communicating systems of pushdown automata of Csuhaj-Varjú et al. These are obtained by using a response symbol in addition to the usual query symbols. Our main result states that centralized asynchronous parallel communicating systems of pushdown automata of degree n that work in returning mode have exactly the same expressive power as n-head pushdown automata. This holds in the nondeterministic as well as in the deterministic case. In addition, it is shown that the class of binary relations that is computed by centralized asynchronous parallel communicating systems of pushdown automata of degree two that are working in returning mode coincides with the class of pushdown relations.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: International Journal of Foundations of Computer Science
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
