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arXiv · 2506.22144

Wait-Only Broadcast Protocols are Easier to Verify

Lucie Guillou·Arnaud Sangnier·Nathalie Sznajder
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Abstract

We study networks of processes that all execute the same finite-state protocol and communicate via broadcasts. We are interested in two problems with a parameterized number of processes: the synchronization problem which asks whether there is an execution which puts all processes on a given state; and the repeated coverability problem which asks if there is an infinite execution where a given transition is taken infinitely often. Since both problems are undecidable in the general case, we investigate those problems when the protocol is Wait-Only, i.e., it has no state from which a process can both broadcast and receive messages. We establish that the synchronization problem becomes Ackermann-complete, and the repeated coverability problem is in EXPSPACE, and PSPACE-hard.

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Lucie Guillou, Arnaud Sangnier, Nathalie Sznajder. 2025-06-27. Wait-Only Broadcast Protocols are Easier to Verify. https://arxiv.org/abs/2506.22144

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