Imperial College London
Professor Nobuko Yoshida

ProfessorNobukoYoshida

Faculty of Engineering, Department of Computing

Academic Visitor
 
 
 
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Contact

 

+44 (0)20 7594 8240n.yoshida Website

 
 
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Location

 

556Huxley BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@inproceedings{Ghilezan:2021:10.1145/3434297,
author = {Ghilezan, S and Pantovi, J and Proki, I and Scalas, A and Yoshida, N},
doi = {10.1145/3434297},
pages = {1--28},
publisher = {Association for Computing Machinery (ACM)},
title = {Precise subtyping for asynchronous multiparty sessions},
url = {http://dx.doi.org/10.1145/3434297},
year = {2021}
}
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RIS format (EndNote, RefMan)

TY  - CPAPER
AB  - Session subtyping is a cornerstone of refinement of communicating processes: a process implementing a session type (i.e., a communication protocol) T can be safely used whenever a process implementing one of its supertypes T′ is expected, in any context, without introducing deadlocks nor other communication errors. As a consequence, whenever T T′ holds, it is safe to replace an implementation of T′ with an implementation of the subtype T, which may allow for more optimised communication patterns.We present the first formalisation of the precise subtyping relation for asynchronous multiparty sessions. We show that our subtyping relation is sound (i.e., guarantees safe process replacement, as outlined above) and also complete: any extension of the relation is unsound. To achieve our results, we develop a novel session decomposition technique, from full session types (including internal/external choices) into single input/output session trees (without choices).Previous work studies precise subtyping for binary sessions (with just two participants), or multiparty sessions (with any number of participants) and synchronous interaction. Here, we cover multiparty sessions with asynchronous interaction, where messages are transmitted via FIFO queues (as in the TCP/IP protocol), and prove that our subtyping is both operationally and denotationally precise. In the asynchronous multiparty setting, finding the precise subtyping relation is a highly complex task: this is because, under some conditions, participants can permute the order of their inputs and outputs, by sending some messages earlier or receiving some later, without causing errors; the precise subtyping relation must capture all such valid permutations — and consequently, its formalisation, reasoning and proofs become challenging. Our session decomposition technique overcomes this complexity, expressing the subtyping relation as a composition of refinement relations between single input/outpu
AU  - Ghilezan,S
AU  - Pantovi,J
AU  - Proki,I
AU  - Scalas,A
AU  - Yoshida,N
DO  - 10.1145/3434297
EP  - 28
PB  - Association for Computing Machinery (ACM)
PY  - 2021///
SN  - 2475-1421
SP  - 1
TI  - Precise subtyping for asynchronous multiparty sessions
UR  - http://dx.doi.org/10.1145/3434297
UR  - http://hdl.handle.net/10044/1/86054
ER  -
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