Relevant Epistemic Logic with Public Announcements and Common Knowledge

2021 ◽  
pp. 342-361
Author(s):  
Vít Punčochář ◽  
Igor Sedlár
Keyword(s):  
Epistemic Logic ◽  
Common Knowledge ◽  
Public Announcements

scholarly journals Playing cards with Hintikka An introduction to dynamic epistemic logic

2005 ◽  
Vol 3 ◽  
Author(s):  
H. P. Ditmarsch ◽  
W. Van Der Hoek ◽  
B. P. Kooi
Keyword(s):  
Epistemic Logic ◽  
Common Knowledge ◽  
Dynamic Epistemic Logic ◽  
Knowledge And Beliefs ◽  
Public Announcements

This contribution is a gentle introduction to so-called dynamic epistemic logics, that can describe how agents change their knowledge and beliefs. We start with a concise introduction to epistemic logic, through the example of one, two and finally three players holding cards; and, mainly for the purpose of motivating the dynamics, we also very summarily introduce the concepts of general and common knowledge. We then pay ample attention to the logic of public announcements, wherein agents change their knowledge as the result of public announcements. One crucial topic in that setting is that of unsuccessful updates: formulas that become false when announced. The Moore-sentences that were already extensively discussed at the conception of epistemic logic in Hintikka’s ‘Knowledge and Belief ’ (1962) give rise to such unsuccessful updates. After that, we present a few examples of more complex epistemic updates.

scholarly journals THE EXPRESSIVITY OF FACTUAL CHANGE IN DYNAMIC EPISTEMIC LOGIC

2013 ◽  
Vol 7 (2) ◽  
pp. 208-221 ◽  
Author(s):  
LOUWE B. KUIJER
Keyword(s):  
Epistemic Logic ◽  
Common Knowledge ◽  
Dynamic Epistemic Logic ◽  
Public Announcements

AbstractA commonly used dynamic epistemic logic is one obtained by adding commonknowledge and public announcements to a basic epistemic logic. It is known from Kooi (2007) that adding public substitutions to such a logic adds expressivity over the class K of models. Here I show that substitutions also add expressivity over the classes KD45, S4 and S5 of models. Since the combination of common knowledge, public announcements and substitutions, was shown in Kooi (2007) to be equally expressive to relativized common knowledge these results also show that relativized common knowledge is more expressive than common knowledge and public announcements over KD45, S4 and S5. These results therefore extend the result from van Benthem et al. (2006) that shows that relativized common knowledge is more expressive than common knowledge and public announcements over K.

scholarly journals Multi-Agent Abstract Argumentation Frameworks With Incomplete Knowledge of Attacks

2021 ◽  
Author(s):  
Andreas Herzig ◽  
Antonio Yuste Ginel
Keyword(s):  
Epistemic Logic ◽  
Partial Information ◽  
Common Knowledge ◽  
Higher Order ◽  
Dynamic Epistemic Logic ◽  
Second Order ◽  
The State ◽  
Incomplete Knowledge ◽  
Abstract Argumentation ◽  
Multi Agent

We introduce a multi-agent, dynamic extension of abstract argumentation frameworks (AFs), strongly inspired by epistemic logic, where agents have only partial information about the conflicts between arguments. These frameworks can be used to model a variety of situations. For instance, those in which agents have bounded logical resources and therefore fail to spot some of the actual attacks, or those where some arguments are not explicitly and fully stated (enthymematic argumentation). Moreover, we include second-order knowledge and common knowledge of the attack relation in our structures (where the latter accounts for the state of the debate), so as to reason about different kinds of persuasion and about strategic features. This version of multi-agent AFs, as well as their updates with public announcements of attacks (more concretely, the effects of these updates on the acceptability of an argument) can be described using S5-PAL, a well-known dynamic-epistemic logic. We also discuss how to extend our proposal to capture arbitrary higher-order attitudes and uncertainty.

scholarly journals ARROW UPDATE LOGIC

2011 ◽  
Vol 4 (4) ◽  
pp. 536-559 ◽  
Author(s):  
BARTELD KOOI ◽  
BRYAN RENNE
Keyword(s):  
Epistemic Logic ◽  
Belief Change ◽  
Common Knowledge ◽  
Dynamic Epistemic Logic ◽  
Epistemic Access ◽  
Multi Agent ◽  
Logic Approach ◽  
Action Models ◽  
Information Change ◽  
Update Logic

We presentArrow Update Logic, a theory of epistemic access elimination that can be used to reason about multi-agent belief change. While the belief-changing “arrow updates” of Arrow Update Logic can be transformed into equivalent belief-changing “action models” from the popular Dynamic Epistemic Logic approach, we prove that arrow updates are sometimes exponentially more succinct than action models. Further, since many examples of belief change are naturally thought of from Arrow Update Logic’s perspective of eliminating access to epistemic possibilities, Arrow Update Logic is a valuable addition to the repertoire of logics of information change. In addition to proving basic results about Arrow Update Logic, we introduce a new notion of common knowledge that generalizes both ordinary common knowledge and the “relativized” common knowledge familiar from the Dynamic Epistemic Logic literature.

scholarly journals Completeness by Modal Definitions. Application to the Epistemic Logic With Hypotheses

2020 ◽  
Vol 23 (65) ◽  
pp. 1-18
Author(s):  
Levan Uridia ◽  
Dirk Walther
Keyword(s):  
Epistemic Logic ◽  
Common Knowledge ◽  
Conditional Logic ◽  
Modal Operator ◽  
Distributed Knowledge ◽  
Topological Structures ◽  
The Common ◽  
Reasoning About Knowledge

We investigate the variant of epistemic logic S5 for reasoning about knowledge under hypotheses. The logic is equipped with a modal operator of necessity that can be parameterized with a hypothesis representing background assumptions. The modal operator can be described as relative necessity and the resulting logic turns out to be a variant of Chellas’ Conditional Logic. We present an axiomatization of the logic and its extension with the common knowledge operator and distributed knowledge operator. We show that the logics are decidable, complete w.r.t. Kripke as well as topological structures. The topological completeness results are obtained by utilizing the Alexandroff connection between preorders and Alexandroff spaces.

scholarly journals Relativized common knowledge for dynamic epistemic logic

2015 ◽  
Vol 13 (3) ◽  
pp. 370-393 ◽  
Author(s):  
Yì N. Wáng ◽  
Thomas Ågotnes
Keyword(s):  
Epistemic Logic ◽  
Common Knowledge ◽  
Dynamic Epistemic Logic

scholarly journals Faultless responsibility: on the nature and allocation of moral responsibility for distributed moral actions

2016 ◽  
Vol 374 (2083) ◽  
pp. 20160112 ◽  
Author(s):  
Luciano Floridi
Keyword(s):  
Moral Responsibility ◽  
Network Theory ◽  
Epistemic Logic ◽  
Data Science ◽  
Common Knowledge ◽  
Strict Liability ◽  
Back Propagation ◽  
Distributed Environments ◽  
Software Platform ◽  
Human Individual

The concept of distributed moral responsibility (DMR) has a long history. When it is understood as being entirely reducible to the sum of (some) human, individual and already morally loaded actions, then the allocation of DMR, and hence of praise and reward or blame and punishment, may be pragmatically difficult, but not conceptually problematic. However, in distributed environments, it is increasingly possible that a network of agents, some human, some artificial (e.g. a program) and some hybrid (e.g. a group of people working as a team thanks to a software platform), may cause distributed moral actions (DMAs). These are morally good or evil (i.e. morally loaded) actions caused by local interactions that are in themselves neither good nor evil (morally neutral). In this article, I analyse DMRs that are due to DMAs, and argue in favour of the allocation, by default and overridably, of full moral responsibility (faultless responsibility) to all the nodes/agents in the network causally relevant for bringing about the DMA in question, independently of intentionality. The mechanism proposed is inspired by, and adapts, three concepts: back propagation from network theory, strict liability from jurisprudence and common knowledge from epistemic logic. This article is part of the themed issue ‘The ethical impact of data science’.

scholarly journals The Logic of Public Announcements, Common Knowledge, and Private Suspicions

2016 ◽  
pp. 773-812 ◽  
Author(s):  
Alexandru Baltag ◽  
Lawrence S. Moss ◽  
Sławomir Solecki
Keyword(s):  
Common Knowledge ◽  
Public Announcements

scholarly journals DYNAMIC GRADED EPISTEMIC LOGIC

2019 ◽  
Vol 12 (4) ◽  
pp. 663-684
Author(s):  
MINGHUI MA ◽  
HANS VAN DITMARSCH
Keyword(s):  
Epistemic Logic ◽  
Dynamic Epistemic Logic ◽  
Kripke Models ◽  
Public Events ◽  
Public Announcements ◽  
Event Models

AbstractGraded epistemic logic is a logic for reasoning about uncertainties. Graded epistemic logic is interpreted on graded models. These models are generalizations of Kripke models. We obtain completeness of some graded epistemic logics. We further develop dynamic extensions of graded epistemic logics, along the framework of dynamic epistemic logic. We give an extension with public announcements, i.e., public events, and an extension with graded event models, a generalization also including nonpublic events. We present complete axiomatizations for both logics.

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