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23-27 January 2006, OzsL Schoolweek, , Hotel Zwartewater, Zwartsluis

Date: 23-27 January 2006
Location: Hotel Zwartewater, Zwartsluis

The main theme of this year's OzsL Schoolweek is Dynamic Epistemic Logic. Outside of the main theme, we offer a palette of tantalizing and stimulating lectures. These lectures present the technical and philosophical Umfeld of the main theme. Moreover, there is the yearly Accolade, organized by the OzsL AIO's, in which our PhD students share their progress with us.

For participation of the schoolweek we ask a fee (+/- 400 euro's per person), which will be paid for PhDstudents by the local group. If you are a PhD student, please contact a representative of your group. (Michael Moortgat, UU; Jan van Eijck, UvA; Frank Veltman, UvA; Jan Treur, VU; Gerard Renardel de Lavalette, RUG; Harry Bunt, KUB; Albert Visser, UU) If you are an advanced student contact your educational institute for a contribution.

Main theme

Epistemic logic is the logic of knowledge. Following Hintikka's book `Knowledge and Belief' (1962) it is common to analyse knowledge and belief as modal operators satisfying certain well known postulates. Knowledge satisfies distribution, positive and negative introspection, truthfulness. Consistent belief satisfies distribution, positive and negative introspection, and consistency. Possibly inconsistent belief satisfies distribution and positive and negative introspection. The logic of knowledge is modelled by S5, that of consistent belief by KD45, and that of mere belief by K45.

Dynamic epistemic logic is the logic of the effects of epistemic actions like making public announcements, passing private messages, revealing secrets, telling lies. Baltag, Moss and Solecki, `The logic of public announcements, common knowledge, and private suspicions' (technical report 1999), showed how to treat all of these in a common framework, in terms of a very general notion of update, by means of action models, of epistemic states, generalizing earlier approaches to the logic of public announcement by Plaza and Gerbrandy. Later, it was shown by Van Benthem, Van Eijck and Kooi (2005) how dynamic epistemic logic can be streamlined and simplified and brought within the framework of epistemic propositional dynamic logic (PDL).

Dynamic epistemic logic is a tool that can be used for modelling how the conceptual space of a group of agents (represented as a labelled transition system, or Kripke model) evolves during a series of epistemic updates. This is useful for solving conceptual puzzles, like the well known muddy children puzzle, but also for analyzing communication protocols by means of epistemic model checking or epistemic theorem proving.

Preliminary Program

The program below may be subject to small changes. There are three timeslots:
slot 1: 10.00-12.00
slot 2: 13.30-15.30
slot 3: 16.00-18.00

January 23:
ACCOLADE in which OzsL PhD students present their research

January 24:
slot 1: Johan van Benthem: Logical Dynamics
slot 2: Jan van Eijck and Simona Orzan: course in Dynamic Epistemic Logic
slot 3: John-Jules Meyer: Logic for Intelligent Agents

January 25:
slot 1: Barteld Kooi: course in Dynamic Epistemic Logic
slot 2: Alexandru Baltag: Epistemic Action Models and the Product Update CONTENT: Epistemic propositions, epistemic updates. Kripke Models for Actions and States. The Update Problem. The Product Update. Examples: public announcements, private (group) announcements, (fair) game announcements, deceiving game announcements, wiretapping, lying.
slot 3: Frank Hindriks: Rule-following and Social Reality CONTENT: rule, concept, rule-following, collective acceptance, reflexivity, performativity, constitution of social reality, constitutive rules, the XYZ-schema, institutions

January 26:
slot 1: Jan van Eijck and Simona Orzan: course in Dynamic Epistemic Logic
slot 2: Alexandru Baltag: Logics for Epistemic Updates CONTENT: Epistemic signatures, and signature-based actions. Operations on epistemic propositions and on epistemi c updates. Operations on epistemic actions. Learning an Action. Signature-based DEL logics: syntax, semantics, proof system. Examples of special-purpose logics. Alternative presentation of DEL: fixed-point notation for actions.
slot 3: Eric Pacuit: Social Interaction, Knowledge, and Social Software

January 27:
slot 1: Jan van Eijck and Simona Orzan: sofware demonstration
slot 2: Alexandru Baltag: Applications, Extensions, Limitations and Open Problems CONTENT: Applications: games, dialogues and puzzles; communication in multi-agent systems; the pragmatics of natural language; secure communications, some examples of applications to cryptographic protocols. Extensions: adding content to messages, fact-changing actions, converse modalities (strongest postconditions), probabilistic updates; dynamic belief revision; logics with conditional knowledge; adding iteration (Kleene star). Limits: incompleteness of DEL with iteration. Open problems.
slot 3: Johan van Benthem: Dynamic Epistemic Logic and Philosophy


Please send an e-mail, BEFORE JANUARY 5 (this is the absolute deadline for registration), with your name, address, phonenumber, position, discipline and institution (University) to:

You will be registrated for the whole week of January 23 - 27, 2006. Please let us know if you participate only for a part of the week (which days?).

For more information, see the OZSL-site at

Please note that this newsitem has been archived, and may contain outdated information or links.