The Experts below are selected from a list of 13194 Experts worldwide ranked by ideXlab platform

Katsuhiko Sano - One of the best experts on this subject based on the ideXlab platform.

  • Dynamic Epistemic Logic of belief change in legal judgments
    Artificial Intelligence and Law, 2018
    Co-Authors: Pimolluck Jirakunkanok, Katsuhiko Sano, Satoshi Tojo
    Abstract:

    This study realizes belief/reliability change of a judge in a legal judgment by dynamic Epistemic Logic (DEL). A key feature of DEL is that possibilities in an agent’s belief can be represented by a Kripke model. This study addresses two difficulties in applying DEL to a legal case. First, since there are several methods for constructing a Kripke model, our question is how we can construct the model from a legal case. Second, since this study employs several dynamic operators, our question is how we can decide which operators are to be applied for belief/reliability change of a judge. In order to solve these difficulties, we have implemented a computer system which provides two functions. First, the system can generate a Kripke model from a legal case. Second, the system provides an inconsistency solving algorithm which can automatically perform several operations in order to reduce the effort needed to decide which operators are to be applied. By our implementation, the above questions can be adequately solved. With our analysis method, six legal cases are analyzed to demonstrate our implementation.

  • axiomatizing Epistemic Logic of friendship via tree sequent calculus
    International Workshop on Logic Rationality and Interaction, 2017
    Co-Authors: Katsuhiko Sano
    Abstract:

    This paper positively solves an open problem if it is possible to provide a Hilbert system to Epistemic Logic of Friendship (EFL) by Seligman, Girard and Liu. To find a Hilbert system, we first introduce a sound, complete and cut-free tree (or nested) sequent calculus for EFL, which is an integrated combination of Seligman’s sequent calculus for basic hybrid Logic and a tree sequent calculus for modal Logic. Then we translate a tree sequent into an ordinary formula to specify a Hilbert system of EFL and finally show that our Hilbert system is sound and complete for an intended two-dimensional semantics.

  • a cut free labelled sequent calculus for dynamic Epistemic Logic
    Foundations of Computer Science, 2016
    Co-Authors: Shoshin Nomura, Hiroakira Ono, Katsuhiko Sano
    Abstract:

    Dynamic Epistemic Logic is a Logic that is aimed at formally expressing how a person’s knowledge changes. We provide a cut-free labelled sequent calculus (\(\mathbf {GDEL}\)) on the background of existing studies of Hilbert-style axiomatization \(\mathbf {HDEL}\) by Baltag et al. (1989) and labelled calculi for Public Announcement Logic by Maffezioli et al. (2011) and Nomura et al. (2015). We first show that the cut rule is admissible in \(\mathbf {GDEL}\). Then we show \(\mathbf {GDEL}\) is sound and complete for Kripke semantics. Lastly, we touch briefly on our on-going work of an automated theorem prover of \(\mathbf {GDEL}\).

Emiliano Lorini - One of the best experts on this subject based on the ideXlab platform.

  • rethinking Epistemic Logic with belief bases
    Artificial Intelligence, 2020
    Co-Authors: Emiliano Lorini
    Abstract:

    Abstract We introduce a new semantics for a family of Logics of explicit and implicit belief based on the concept of multi-agent belief base. Differently from standard semantics for Epistemic Logic in which the notions of possible world and doxastic/Epistemic alternative are primitive, in our semantics they are non-primitive but are computed from the concept of belief base. We provide complete axiomatizations and prove decidability for our Logics via finite model arguments. Furthermore, we provide polynomial embeddings of our Logics into Fagin & Halpern's Logic of general awareness and establish complexity results via the embeddings. We also present variants of the Logics incorporating different forms of Epistemic introspection for explicit and/or implicit belief and provide complexity results for some of these variants. Finally, we present a number of dynamic extensions of the static framework by informative actions of both public and private type, including public announcement, belief base expansion and forgetting. We illustrate the application potential of the Logical framework with the aid of a concrete example taken from the domain of conversational agents.

  • exploiting belief bases for building rich Epistemic structures
    Theoretical Aspects of Rationality and Knowledge, 2019
    Co-Authors: Emiliano Lorini
    Abstract:

    We introduce a semantics for Epistemic Logic exploiting a belief base abstraction. Differently from existing Kripke-style semantics for Epistemic Logic in which the notions of possible world and epis-temic alternative are primitive, in the proposed semantics they are non-primitive but are defined from the concept of belief base. We show that this semantics allows us to define the universal Epistemic model in a simpler and more compact way than existing inductive constructions of it. We provide (i) a number of semantic equivalence results for both the basic Epistemic language with 'individual be-lief' operators and its extension by the notion of 'only believing', and (ii) a lower bound complexity result for Epistemic Logic model checking relative to the universal Epistemic model.

  • sat for Epistemic Logic using belief bases
    7th International Workshop on Engineering Multi-Agent Systems (EMAS 2019), 2019
    Co-Authors: Emiliano Lorini, Fabian Romero
    Abstract:

    In [4] a new Epistemic Logic \(\textsf {LDA}\) of explicit and implicit belief was introduced, and in [5] we presented a tableau-based satisfability checking procedure as well as a dynamic extension for it. Based on such procedure, we created a portable software implementation that works for the family of multi-agent Epistemic Logics, as well as for the proposed dynamic extension. This software implementation runs as a library for the most common operative systems, also runs in popular IoT and robot hardware, as well as cloud environments and in server-less configurations.

  • Decision Procedures for Epistemic Logic Exploiting Belief Bases
    2019
    Co-Authors: Emiliano Lorini, Benito Fabian Romero Jimenez
    Abstract:

    We provide tableau-based PSPACE satisfiability checking procedures for a family of multi-agent Epistemic Logics with a semantics defined in terms of belief bases. Such Logics distinguish an agent's explicit beliefs, i.e., all facts included in the agent's belief base, from the agent's implicit beliefs, i.e., all facts deducible from the agent's belief base. We provide a simple dynamic extension for one of these Logics by propositional assignments performed by agents. A propo-sitional assignment captures a simple form of action that changes not only the environment but also the agents' beliefs depending on how they jointly perceive its execution. After having provided a PSPACE satisfiability checking procedure for this dynamic extension , we show how it can be used in human-robot interaction in which both the human and the robot have higher-order beliefs about the other's beliefs and can modify the environment by acting.

  • a poor man s Epistemic Logic based on propositional assignment and higher order observation
    5th International Conference on Logic Rationality and Interaction (LORI 2015), 2015
    Co-Authors: Andreas Herzig, Emiliano Lorini, Faustine Maffre
    Abstract:

    We introduce a dynamic Epistemic Logic that is based on what an agent can observe, including joint observation and observation of what other agents observe. This generalizes van der Hoek, Wooldridge and colleague’s Logics ECL-PC(PO) and LRC where it is common knowledge which propositional variables each agent observes. In our Logic, facts of the world and their observability can both be modified by assignment programs. We show how Epistemic operators can be interpreted in this framework and identify the conditions under which the principles of positive and negative introspection are valid. We also provide a sound and complete axiomatization and prove that the satisfiability problem is PSpace-complete. Finally, we show how public and private announcements can be expressed and illustrate the latter by the gossip spreading problem.

Hans Van Ditmarsch - One of the best experts on this subject based on the ideXlab platform.

  • undecidability for arbitrary public announcement Logic
    Advances in Modal Logic, 2008
    Co-Authors: Tim French, Hans Van Ditmarsch
    Abstract:

    Arbitrary public announcement Logic (AP AL) is an extension of multi-agent Epistemic Logic that allows agents' knowledge states to be updated by the public announcement of (possibly arbitrary) Epistemic for- mulae. It has been shown to be more expressive than Epistemic Logic, and a sound and complete axiomatization has been given. Here we address the question of decidability. We present a proof that the satisfiability problem for arbitrary public announcement Logic (AP AL) is co-RE complete, via a tiling argument.

  • a tableau method for public announcement Logics
    Theorem Proving with Analytic Tableaux and Related Methods, 2007
    Co-Authors: Philippe Balbiani, Andreas Herzig, Hans Van Ditmarsch, Tiago De Lima
    Abstract:

    Public announcement Logic is an extension of multi-agent Epistemic Logic with dynamic operators to model the informational consequences of announcements to the entire group of agents. We propose a labelled tableau-calculus for this Logic. We also present an extension of the calculus for a Logic of arbitrary announcements.

Alexey Yatmanov - One of the best experts on this subject based on the ideXlab platform.

  • sequent calculus for intuitionistic Epistemic Logic iel
    Foundations of Computer Science, 2016
    Co-Authors: Vladimir N. Krupski, Alexey Yatmanov
    Abstract:

    The formal system of intuitionistic Epistemic Logic IEL was proposed by S. Artemov and T. Protopopescu. It provides the formal foundation for the study of knowledge from an intuitionistic point of view based on Brouwer-Hayting-Kolmogorov semantics of intuitionism. We construct a cut-free sequent calculus for IEL and establish that polynomial space is sufficient for the proof search in it. We prove that IEL is PSPACE-complete.

Wang Zhixue - One of the best experts on this subject based on the ideXlab platform.

  • symbolic model checking algorithm for temporal Epistemic Logic ctl k
    Computer Science, 2009
    Co-Authors: Wang Zhixue
    Abstract:

    Temporal Epistemic Logics have been gradually used in specification of multiple agents system,which are composed by temporal Logics and Epistemic Logics.Most of temporal Epistemic Logics are based on CTL,which have a limited expressivity.And some model checking techniques existing for them have problems such as memory-shortage and state-explosion.A temporal Epistemic Logic CTL*K based on CTL* was proposed.Through the definition of syntax and semantics,CTL*K had a strong expressivity and could describe agents' Epistemic properties such as belief and goal.To check CTL*K,a symbolic model checking algorithm for CTL*K was offered,which translated a CTL*K formula into a common CTL* formula and could be easily encoded into NuSMV model checker.The experiment showed that the algorithm could obviously enlarge the size of system to be checked.