721 research outputs found
Asynchronous Announcements
We propose a multi-agent epistemic logic of asynchronous announcements, where
truthful announcements are publicly sent but individually received by agents,
and in the order in which they were sent. Additional to epistemic modalities
the logic contains dynamic modalities for making announcements and for
receiving them. What an agent believes is a function of her initial uncertainty
and of the announcements she has received. Beliefs need not be truthful,
because announcements already made may not yet have been received. As
announcements are true when sent, certain message sequences can be ruled out,
just like inconsistent cuts in distributed computing.
We provide a complete axiomatization for this \emph{asynchronous announcement
logic} (AA). It is a reduction system that also demonstrates that any formula
in is equivalent to one without dynamic modalities, just as for public
announcement logic. The model checking complexity is in PSPACE. A detailed
example modelling message exchanging processes in distributed computing in
closes our investigation
To Be Announced
In this survey we review dynamic epistemic logics with modalities for
quantification over information change. Of such logics we present complete
axiomatizations, focussing on axioms involving the interaction between
knowledge and such quantifiers, we report on their relative expressivity, on
decidability and on the complexity of model checking and satisfiability, and on
applications. We focus on open problems and new directions for research
Hidden protocols: Modifying our expectations in an evolving world
When agents know a protocol, this leads them to have expectations about future observations. Agents can update their knowledge by matching their actual observations with the expected ones. They eliminate states where they do not match. In this paper, we study how agents perceive protocols that are not commonly known, and propose a semantics-driven logical framework to reason about knowledge in such scenarios. In particular, we introduce the notion of epistemic expectation models and a propositional dynamic logic-style epistemic logic for reasoning about knowledge via matching agentsÊ expectations to their observations. It is shown how epistemic expectation models can be obtained from epistemic protocols. Furthermore, a characterization is presented of the effective equivalence of epistemic protocols. We introduce a new logic that incorporates updates of protocols and that can model reasoning about knowledge and observations. Finally, the framework is extended to incorporate fact-changing actions, and a worked-out example is given. © 2013 Elsevier B.V
- …