Learning What Others Know

TL;DR

This paper develops advanced dynamic-epistemic logics to model multi-agent information sharing, including epistemic superiority and complex informational actions like hacking, with complete axiomatizations and decidability results.

Contribution

It introduces novel dynamic-epistemic logics incorporating comparative epistemic assertions and models complex information-sharing actions, including hacking, with formal axiomatizations.

Findings

Complete axiomatizations of the proposed logics

Decidability of the logics established

Modeling of complex informational actions like hacking

Abstract

We propose a number of powerful dynamic-epistemic logics for multi-agent information sharing and acts of publicly or privately accessing other agents' information databases. The static base of our logics is obtained by adding to standard epistemic logic comparative epistemic assertions, that can express epistemic superiority between groups or individuals, as well as a common distributed knowledge operator (that combines features of both common knowledge and distributed knowledge). On the dynamic side, we introduce actions by which epistemic superiority can be acquired: "sharing all one knows" (by e.g. giving access to one's information database to all or some of the other agents), as well as more complex informational events, such as hacking. We completely axiomatize several such logics and prove their decidability.