Coalition and Group Announcement Logic

TL;DR

This paper introduces a combined logic of coalition and group announcements, providing a complete axiomatisation and exploring their interactions, advancing understanding of multi-agent knowledge dynamics.

Contribution

It presents a new combined logic called Coalition and Relativised Group Announcement Logic with a complete axiomatisation and addresses open questions about operator interactions.

Findings

Provided a complete axiomatisation of the combined logic

Partially answered questions on operator interactions

Settled some open problems in the field

Abstract

Dynamic epistemic logics which model abilities of agents to make various announcements and influence each other's knowledge have been studied extensively in recent years. Two notable examples of such logics are Group Announcement Logic and Coalition Announcement Logic. They allow us to reason about what groups of agents can achieve through joint announcements in non-competitive and competitive environments. In this paper, we consider a combination of these logics -- Coalition and Relativised Group Announcement Logic and provide its complete axiomatisation. Moreover, we partially answer the question of how group and coalition announcement operators interact, and settle some other open problems.