On the expressive power of movement and restriction in pure mobile ambients

  • Authors:

  • Nadia Busi;Gianluigi Zavattaro

  • Affiliations:

  • Dipartimento di Scienze dell'Informazione, Università di Bologna, Mura Anteo Zamboni 7, I-40127 Bologna, Italy;Dipartimento di Scienze dell'Informazione, Università di Bologna, Mura Anteo Zamboni 7, I-40127 Bologna, Italy

  • Venue:
  • Theoretical Computer Science - Special issue: Foundations of wide area network computing
  • Year:
  • 2004

Quantified Score

Hi-index 0.00

Visualization

Abstract

Pure mobile ambients is a process calculus suitable to focus on issues related to mobility, abstracting away from aspects concerning process communication. However, it incorporates name restriction (i.e. the (vn) binder) and ambient movement (i.e. the in and out capabilities) that can be seen as characteristics adapted, or directly borrowed, from the tradition of communication-based process calculi. For this reason, we retain that it is worth to investigate whether or not these features can be removed from pure mobile ambients without losing expressive power.To this aim, we consider two variants of pure mobile ambients which differ in the way infinite processes can be defined; the former exploits process replication, while the latter is more general and permits recursive process definition. We analyse whether or not the elimination of ambient movement and/or name restriction reduces the expressive power of these two calculi, using the decidability of process termination as a yardstick. We prove that name restriction can be removed from both calculi without reducing the expressive power. On the other hand, the elimination of both ambient movement and name restriction strictly reduces the expressive power of both calculi. As far as the elimination of only ambient movement is concerned, we prove an interesting discrimination result: process termination is undecidable under recursive process definition, while it turns out to be decidable under process replication.