,
Hugo Paquet
Creative Commons Attribution 4.0 International license
Continuation semantics for simple programming languages can be axiomatized as a dialogue category: a symmetric monoidal category equipped with a negation operation. This axiomatization makes clear the relationship between game semantics, CPS transformations, and continuation monads. In this paper we extend dialogue categories with 2-categorical structure and concurrent primitives. This is inspired by a recent analysis of concurrency based on 2-categorical monads. We show that the fine-grained structure of dialogue categories, not generally available in other semantic models, can be exploited to give a type to concurrent primitives join and fork. Our main theorem is that this simple axiomatization induces a concurrent continuation 2-monad. We also show that this framework is expressive beyond call-by-value monadic programming. The definitions in this paper are illustrated by concrete constructions in concurrent game semantics, and our results give a formal categorical basis for concurrent strategies. From a more practical perspective, our approach suggests a candidate target language for linear CPS transformations of concurrent programming languages.
@InProceedings{breuvart_et_al:LIPIcs.FSCD.2025.10,
author = {Breuvart, Flavien and Paquet, Hugo},
title = {{Categorical Continuation Semantics for Concurrency}},
booktitle = {10th International Conference on Formal Structures for Computation and Deduction (FSCD 2025)},
pages = {10:1--10:21},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-374-4},
ISSN = {1868-8969},
year = {2025},
volume = {337},
editor = {Fern\'{a}ndez, Maribel},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.FSCD.2025.10},
URN = {urn:nbn:de:0030-drops-236251},
doi = {10.4230/LIPIcs.FSCD.2025.10},
annote = {Keywords: denotational semantics, 2-categories, concurrency, continuations, game semantics}
}