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Exploring the update universe
 Master’s thesis
, 2004
"... 1.1 General issues........................... 5 ..."
Action emulation
 CWI and ILLC, Amsterdam & Department of Economics
, 2004
"... Abstract. The effects of public announcements, private communications, deceptive messages to groups, and so on, can all be captured by a general mechanism of updating multiagent models with update action models [3], now in widespread use (see [10] for a textbook treatment). There is a natural exten ..."
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Cited by 12 (5 self)
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Abstract. The effects of public announcements, private communications, deceptive messages to groups, and so on, can all be captured by a general mechanism of updating multiagent models with update action models [3], now in widespread use (see [10] for a textbook treatment). There is a natural extension of the definition of a bisimulation to action models. Surely enough, updating with bisimilar action models gives the same result (modulo bisimulation). But the converse turns out to be false: update models may have the same update effects without being bisimilar. We propose action emulation as a notion of structural equivalence more appropriate for action models, and generalizing standard bisimulation. It is proved that action emulation provides a full characterization of update effect, provided we confine attention to ‘smooth ’ action models. We also give a recipe for turning any action model into a smooth one with the same update effect. Together, this yields a simplification procedure for action models, and it gives designers of multiagent systems a useful tool for comparing different ways of representing a particular communicative action. 1.
Reducing dynamic epistemic logic to PDL by program transformation
 IN [VE005
, 2004
"... We present a direct reduction of dynamic epistemic logic in the spirit of [4] to propositional dynamic logic (PDL) [17, 18] by program transformation. The program transformation approach associates with every update action a transformation on PDL programs. These transformations are then employed in ..."
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Cited by 8 (6 self)
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We present a direct reduction of dynamic epistemic logic in the spirit of [4] to propositional dynamic logic (PDL) [17, 18] by program transformation. The program transformation approach associates with every update action a transformation on PDL programs. These transformations are then employed in reduction axioms for the update actions. It follows that the logic of public announcement, the logic of group announcements, the logic of secret message passing, and so on, can all be viewed as subsystems of PDL. Moreover, the program transformation approach can be used to generate the appropriate reduction axioms for these logics. Our direct reduction of dynamic epistemic logic to PDL was inspired by the reduction of dynamic epistemic logic to automata PDL of [13]. Our approach shows how the detour through automata can be avoided.
Chapter 1 On the Logic of Lying
"... Abstract We model lying as a communicative act changing the beliefs of the agents in a multiagent system. With Augustine, we see lying as an utterance believed to be false by the speaker and uttered with the intent to deceive the addressee. The deceit is successful if the lie is believed after the ..."
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Abstract We model lying as a communicative act changing the beliefs of the agents in a multiagent system. With Augustine, we see lying as an utterance believed to be false by the speaker and uttered with the intent to deceive the addressee. The deceit is successful if the lie is believed after the utterance by the addressee. This is our perspective. Also, as common in dynamic epistemic logics, we model the agents addressed by the lie, but we do not (necessarily) model the speaker as one of those agents. This further simplifies the picture: we do not need to model the intention of the speaker, nor do we need to distinguish between knowledge and belief of the speaker: he is the observer of the system and his beliefs are taken to be the truth by the listeners. We provide a sketch of what goes on logically when a lie is communicated. We present a complete logic of manipulative updating, to analyse the effects of lying in public discourse. Next, we turn to the study of lying in games. First, a gametheoretical analysis is used to explain how the possibility of lying makes games such as Liar’s Dice interesting, and how lying is put to use in optimal strategies for playing the game. This is the opposite of the logical manipulative update: instead of always believing the utterance, now, it is never believed. We also give a matching logical analysis for the games perspective, and implement that in the model checker DEMO. Our running example of lying in games is the game of Liar’s Dice.
Analyzing Communication with Dynamic Epistemic Logic
, 2006
"... This paper introduces and documents DEMO, a Dynamic Epistemic Modelling tool. DEMO allows modelling epistemic updates, graphical display of update results, graphical display of action models, formula evaluation in epistemic models, translation of dynamic epistemic formulas to PDL formulas. Also, DEM ..."
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This paper introduces and documents DEMO, a Dynamic Epistemic Modelling tool. DEMO allows modelling epistemic updates, graphical display of update results, graphical display of action models, formula evaluation in epistemic models, translation of dynamic epistemic formulas to PDL formulas. Also, DEMO implements the reduction of dynamic epistemic logic [22, 2, 3, 1] to PDL given in [17] and presented in the context of generic languages for communication and change in [6]. Epistemic models are minimized under bisimulation, and update action models are simplified under action emulation (an appropriate structural notion for having the same update effect, cf. [19]). The paper is an exemplar of tool building for epistemic update logic. It contains the essential code of an implementation in Haskell [29], in ‘literate programming’ style [30], of DEMO.
unknown title
, 2004
"... This paper introduces DEMO, a Dynamic Epistemic Modelling tool. DEMO allows modelling epistemic updates, graphical display of update results, graphical display of action models, formula evaluation in epistemic models, translation of dynamic epistemic formulas to PDL formulas, and so on. The paper im ..."
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This paper introduces DEMO, a Dynamic Epistemic Modelling tool. DEMO allows modelling epistemic updates, graphical display of update results, graphical display of action models, formula evaluation in epistemic models, translation of dynamic epistemic formulas to PDL formulas, and so on. The paper implements the reduction of dynamic epistemic logic [16, 2, 3, 1] to PDL given in [12]. The reduction of dynamic epistemic logic to automata PDL from [24] is also discussed and implemented. Epistemic models are minimized under bisimulation, and update action models are minimized under action emulation (the appropriate structural notion for having the same update effect, cf. [13]). The paper is an exemplar of tool building for epistemic update logic. It contains the full code of an implementation in Haskell [22], in ‘literate programming ’ style [23], of DEMO.
1 2
, 2004
"... A key notion of equivalence for modal and epistemic logic is bisimulation. However, to capture the update effects of action models in epistemic update logic, this notion turns out to be too strong. We propose a notion of equivalence, called action emulation, which is more appropriate for action mode ..."
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A key notion of equivalence for modal and epistemic logic is bisimulation. However, to capture the update effects of action models in epistemic update logic, this notion turns out to be too strong. We propose a notion of equivalence, called action emulation, which is more appropriate for action models than bisimulation. Next, we propose the necessary and sufficient conditions for having the same update effect, in the cases of action models with propositional preconditions and action models with modal preconditions. It is proved that every bisimulation is an action emulation, but not vice versa, and that in the context of action models with propositional or modal preconditions, action emulation provides a full characterization of update effect. Finally we define model contraction which preserves the same update effect.
1 2
, 2004
"... A key notion of equivalence for modal and epistemic logic is bisimulation. However, to capture the update effects of action models in epistemic update logic, this notion turns out to be too strong. We propose a notion of equivalence, called action emulation, which is more appropriate for action mode ..."
Abstract
 Add to MetaCart
A key notion of equivalence for modal and epistemic logic is bisimulation. However, to capture the update effects of action models in epistemic update logic, this notion turns out to be too strong. We propose a notion of equivalence, called action emulation, which is more appropriate for action models than bisimulation. Next, we propose the necessary and sufficient conditions for having the same update effect, in the cases of action models with propositional preconditions and action models with modal preconditions. It is proved that every bisimulation is an action emulation, but not vice versa, and that in the context of action models with propositional or modal preconditions, action emulation provides a full characterization of update effect. Finally we define model contraction which preserves the same update effect.