The Undecidability of Quantified Announcements

Fuente: arXiv
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Main Authors: Ågotnes, Thomas, van Ditmarsch, Hans, French, Tim
Format: Preprint
Published: 2024
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_version_ 1866929375913443328
author Ågotnes, Thomas
van Ditmarsch, Hans
French, Tim
author_facet Ågotnes, Thomas
van Ditmarsch, Hans
French, Tim
contents This paper demonstrates the undecidability of a number of logics with quantification over public announcements: arbitrary public announcement logic (APAL), group announcement logic (GAL), and coalition announcement logic (CAL). In APAL we consider the informative consequences of any announcement, in GAL we consider the informative consequences of a group of agents (this group may be a proper subset of the set of all agents) all of which are simultaneously (and publicly) making known announcements. So this is more restrictive than APAL. Finally, CAL is as GAL except that we now quantify over anything the agents not in that group may announce simultaneously as well. The logic CAL therefore has some features of game logic and of ATL. We show that when there are multiple agents in the language, the satisfiability problem is undecidable for APAL, GAL, and CAL. In the single agent case, the satisfiability problem is decidable for all three logics. This paper corrects an error to the submitted version of Undecidability of Quantified Announcements, identified by Yuta Asami . The nature of the error was in the definition of the formula $cga(X)$ (see Subsection 5.2) which is corrected in this version.
format Preprint
id arxiv_https___arxiv_org_abs_2405_15671
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The Undecidability of Quantified Announcements
Ågotnes, Thomas
van Ditmarsch, Hans
French, Tim
Logic in Computer Science
This paper demonstrates the undecidability of a number of logics with quantification over public announcements: arbitrary public announcement logic (APAL), group announcement logic (GAL), and coalition announcement logic (CAL). In APAL we consider the informative consequences of any announcement, in GAL we consider the informative consequences of a group of agents (this group may be a proper subset of the set of all agents) all of which are simultaneously (and publicly) making known announcements. So this is more restrictive than APAL. Finally, CAL is as GAL except that we now quantify over anything the agents not in that group may announce simultaneously as well. The logic CAL therefore has some features of game logic and of ATL. We show that when there are multiple agents in the language, the satisfiability problem is undecidable for APAL, GAL, and CAL. In the single agent case, the satisfiability problem is decidable for all three logics. This paper corrects an error to the submitted version of Undecidability of Quantified Announcements, identified by Yuta Asami . The nature of the error was in the definition of the formula $cga(X)$ (see Subsection 5.2) which is corrected in this version.
title The Undecidability of Quantified Announcements
topic Logic in Computer Science
url https://arxiv.org/abs/2405.15671