Distributability of mobile ambients

• Published in: Information and computation Vol. 275; p. 104608
• Main Authors: Peters, Kirstin, Nestmann, Uwe
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.12.2020
• Subjects: Distribution; Encodings; Expressive power; Mobile ambients; Process calculi; Encodings; Expressive power; Mobile ambients; Distribution; Process calculi
• ISSN: 0890-5401; 1090-2651
• DOI: 10.1016/j.ic.2020.104608

Modern society is dependent on distributed software systems and to verify them different modelling languages such as mobile ambients were developed. They focus on mobility by allowing both a dynamic network topology as well as the movement of code within the network. To analyse the quality of mobile ambients as a good foundational model for distributed computation, we analyse the level of synchronisation between distributed components that they can express. Therefore, we rely on earlier established synchronisation patterns. It turns out that mobile ambients are not fully distributed, because they can express enough synchronisation to express a synchronisation pattern called M. However, they can express strictly less synchronisation than the pi-calculus. For this reason, we can show that there is no good and distributability-preserving encoding from the pi-calculus into mobile ambients and also no such encoding from mobile ambients into the join-calculus, i.e., the expressive power of mobile ambients is in between these languages. Finally, we discuss how these results can be used to obtain a fully distributed variant of mobile ambients and present one example. Such a fully distributed variant of mobile ambients is a good foundation for distributed computation.