Forms of Generic Common Knowledge

Item

Title
Forms of Generic Common Knowledge
Identifier
d_2009_2013:d6351088ee29:11717
identifier
12322
Creator
Antonakos, Evangelia,
Contributor
Linda Keen
Date
2013
Language
English
Publisher
City University of New York.
Subject
Mathematics | Logic | common knowledge | epistemic logic | generic common knowledge | justification logic | modal logic
Abstract
In multi-agent epistemic logics, common knowledge has been a central consideration of study. A generic common knowledge (G.C.K.) system is one that yields iterated knowledge I(ϕ): 'any agent knows that any agent knows that any agent knows. . . ϕ' for any number of iterations. Generic common knowledge yields iterated knowledge G.C.K.(ϕ) → I(ϕ) but is not necessarily logically equivalent to it. This contrasts with the most prevalent formulation of common knowledge C as equivalent to iterated knowledge. A spectrum of systems may satisfy the G.C.K. condition, of which C is just one. It has been shown that in the usual epistemic scenarios, G.C.K. can replace conventional common knowledge and Artemov has noted that such standard sources of common knowledge as public announcements of atomic sentences generally yield G.C.K. rather than C..;In this dissertation we study mathematical properties of generic common knowledge and compare them to the traditional common knowledge notion. In particular, we contrast the modal G.C.K. logics of McCarthy (e.g. M4) and Artemov (e.g. S4Jn ) with C-systems (e.g. S4Cn ) and present a joint C/G.C.K. implicit knowledge logic S4CJn as a conservative extension of both. We show that in standard epistemic scenarios in which common knowledge of certain premises is assumed, whose conclusion does not concern common knowledge (such as Muddy Children, Wise Men, Unfaithful Wives, etc.), a lighter G.C.K.can be used instead of the traditional, more complicated, common knowledge. We then present the first fully explicit G.C.K. system LP n(LP). This justification logic realizes the corresponding modal system S4Jn so that G.C.K., along with individual knowledge modalities, can always be made explicit.
Type
dissertation
Source
2009_2013.csv
degree
Ph.D.
Program
Mathematics