21,750 research outputs found

    Hidden protocols: Modifying our expectations in an evolving world

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    When agents know a protocol, this leads them to have expectations about future observations. Agents can update their knowledge by matching their actual observations with the expected ones. They eliminate states where they do not match. In this paper, we study how agents perceive protocols that are not commonly known, and propose a semantics-driven logical framework to reason about knowledge in such scenarios. In particular, we introduce the notion of epistemic expectation models and a propositional dynamic logic-style epistemic logic for reasoning about knowledge via matching agentsÊ expectations to their observations. It is shown how epistemic expectation models can be obtained from epistemic protocols. Furthermore, a characterization is presented of the effective equivalence of epistemic protocols. We introduce a new logic that incorporates updates of protocols and that can model reasoning about knowledge and observations. Finally, the framework is extended to incorporate fact-changing actions, and a worked-out example is given. © 2013 Elsevier B.V

    Information completeness in Nelson algebras of rough sets induced by quasiorders

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    In this paper, we give an algebraic completeness theorem for constructive logic with strong negation in terms of finite rough set-based Nelson algebras determined by quasiorders. We show how for a quasiorder RR, its rough set-based Nelson algebra can be obtained by applying the well-known construction by Sendlewski. We prove that if the set of all RR-closed elements, which may be viewed as the set of completely defined objects, is cofinal, then the rough set-based Nelson algebra determined by a quasiorder forms an effective lattice, that is, an algebraic model of the logic E0E_0, which is characterised by a modal operator grasping the notion of "to be classically valid". We present a necessary and sufficient condition under which a Nelson algebra is isomorphic to a rough set-based effective lattice determined by a quasiorder.Comment: 15 page

    "True" as Ambiguous

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    In this paper, I argue (a) that the predicate “true” is ambiguously used to express a deflationary and a substantial concept of truth and (b) that the two concepts are systematically related in that substantial truths are deflationary truths of a certain kind. Claim (a) allows one to accept the main insights of deflationism but still take seriously, and participate in, the traditional debate about the nature of truth. Claim (b) is a contribution to that debate. The overall position is not new and it has previously been defended by supervaluationists about vagueness. However, the position is here motivated in a new, independent way, and an explanation is offered why some uses of “true” do not seem to require disambiguation
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