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A Sound Algorithm for Asynchronous Session Subtyping

Bravetti, Mario, Carbone, Marco, Lange, Julien, Yoshida, Nobuko, Zavattaro, Gianluigi (2019) A Sound Algorithm for Asynchronous Session Subtyping. In: Fokkink, Wan and van Glabbeek, Rob, eds. Leibniz International Proceedings in Informatics. 140. LIPICS ISBN 978-3-95977-121-4. (doi:10.4230/LIPIcs.CONCUR.2019.34) (KAR id:75503)


Session types, types for structuring communication between endpoints in distributed systems, are recently being integrated into mainstream programming languages. In practice, a very important notion for dealing with such types is that of subtyping, since it allows for typing larger classes of

system, where a program has not precisely the expected behavior but a similar one. Unfortunately, recent work has shown that subtyping for session types in an asynchronous setting is undecidable. To cope with this negative result, the only approaches we are aware of either restrict the syntax

of session types or limit communication (by considering forms of bounded asynchrony). Both approaches are too restrictive in practice, hence we proceed differently by presenting an algorithm for checking subtyping which is sound, but not complete (in some cases it terminates without returning a decisive verdict). The algorithm is based on a tree representation of the coinductive definition of asynchronous subtyping; this tree could be infinite, and the algorithm checks for the presence of finite witnesses of infinite successful subtrees. Furthermore, we provide a tool that implements our algorithm and we apply it to many examples that cannot be managed with the previous approaches.

Item Type: Conference or workshop item (Paper)
DOI/Identification number: 10.4230/LIPIcs.CONCUR.2019.34
Uncontrolled keywords: Session types, Concurrency, Subtyping, Algorithm.
Divisions: Divisions > Division of Computing, Engineering and Mathematical Sciences > School of Computing
Depositing User: Julien Lange
Date Deposited: 23 Jul 2019 09:39 UTC
Last Modified: 16 Feb 2021 14:06 UTC
Resource URI: (The current URI for this page, for reference purposes)

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