De Re Updates

TL;DR

This paper introduces a lightweight dynamic epistemic logic that distinguishes between de dicto and de re knowledge and updates, with complete axiomatizations for related public announcement and event-model logics.

Contribution

It presents a novel dynamic epistemic logic incorporating de re and de dicto distinctions with complete axiomatizations, extending previous work with new reduction axioms.

Findings

Complete axiomatizations achieved for the logic variants

New reduction axioms handle interactions between dynamics and assignments

Logic effectively captures de re and de dicto distinctions in knowledge and updates

Abstract

In this paper, we propose a lightweight yet powerful dynamic epistemic logic that captures not only the distinction between de dicto and de re knowledge but also the distinction between de dicto and de re updates. The logic is based on the dynamified version of an epistemic language extended with the assignment operator borrowed from dynamic logic, following the work of Wang and Seligman (Proc. AiML 2018). We obtain complete axiomatizations for the counterparts of public announcement logic and event-model-based DEL based on new reduction axioms taking care of the interactions between dynamics and assignments.