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43Disentangling FDE -Based Paraconsistent Modal LogicsStudia Logica 105 (6): 1221-1254. 2017.The relationships between various modal logics based on Belnap and Dunn’s paraconsistent four-valued logic FDE are investigated. It is shown that the paraconsistent modal logic \, which lacks a primitive possibility operator \, is definitionally equivalent with the logic \, which has both \ and \ as primitive modalities. Next, a tableau calculus for the paraconsistent modal logic KN4 introduced by L. Goble is defined and used to show that KN4 is definitionally equivalent with \ without the absur…Read more
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2"This volume comprises the proceedings of the First All-Berlin Workshop on Nonclassical Logics and Information Processing, held at the Free University of Berlin, November 9-10, 1990. The scope of the ten papers in the volume is broad, covering various different subfields of logic - particularly nonclassical logic - and its applications in artificial intelligence. The papers are grouped according to the four major topics that emerged at the meeting: modal systems, logic programming, nonmonotonic …Read more
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40Proof theory of modal logic (edited book)Kluwer Academic Publishers. 1996.Proof Theory of Modal Logic is devoted to a thorough study of proof systems for modal logics, that is, logics of necessity, possibility, knowledge, belief, time, computations etc. It contains many new technical results and presentations of novel proof procedures. The volume is of immense importance for the interdisciplinary fields of logic, knowledge representation, and automated deduction.
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62Reprint of: A more general general proof theoryJournal of Applied Logic 25 23-46. 2017.In this paper it is suggested to generalize our understanding of general (structural) proof theory and to consider it as a general theory of two kinds of derivations, namely proofs and dual proofs. The proposal is substantiated by (i) considerations on assertion, denial, and bi-lateralism, (ii) remarks on compositionality in proof-theoretic semantics, and (iii) comments on falsification and co-implication. The main formal result of the paper is a normal form theorem for the natural deduction pro…Read more
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9Dag Prawitz on Proofs and Meaning (edited book)Springer. 2015.This volume is dedicated to Prof. Dag Prawitz and his outstanding contributions to philosophical and mathematical logic. Prawitz's eminent contributions to structural proof theory, or general proof theory, as he calls it, and inference-based meaning theories have been extremely influential in the development of modern proof theory and anti-realistic semantics. In particular, Prawitz is the main author on natural deduction in addition to Gerhard Gentzen, who defined natural deduction in his PhD t…Read more
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14Advances in Modal Logic, Volume 2: Papers From the Second Aiml Conference, Held at the University of Uppsala, Sweden, October 1998 (edited book)Center for the Study of Language and Inf. 2001.Modal Logic, originally conceived as the logic of necessity and possibility, has developed into a powerful mathematical and computational discipline. It is the main source of formal languages aimed at analyzing complex notions such as common knowledge and formal provability. Modal and modal-like languages also provide us with families of restricted description languages for relational and topological structures; they are being used in many disciplines, ranging from artificial intelligence, compu…Read more
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20Inconsistency-tolerant description logic. Part II: A tableau algorithm for CALC CJournal of Applied Logic 6 (3): 343-360. 2008.
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88Constructive negation, implication, and co-implicationJournal of Applied Non-Classical Logics 18 (2-3): 341-364. 2008.In this paper, a family of paraconsistent propositional logics with constructive negation, constructive implication, and constructive co-implication is introduced. Although some fragments of these logics are known from the literature and although these logics emerge quite naturally, it seems that none of them has been considered so far. A relational possible worlds semantics as well as sound and complete display sequent calculi for the logics under consideration are presented.
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24Combining linear-time temporal logic with constructiveness and paraconsistencyJournal of Applied Logic 8 (1): 33-61. 2010.
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32Agency and deontic logic, J.f. HortyJournal of Logic, Language and Information 13 (3): 379-381. 2004.
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205Normative Verantwortung für Handlungen Anderer. Eine Untersuchung im Rahmen der stit -TheorieFacta Philosophica 7 (2): 167-187. 2005.
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87Doxastic Decisions, Epistemic Justification, and The Logic of AgencyPhilosophical Studies 128 (1): 201-227. 2006.A prominent issue in mainstream epistemology is the controversy about doxastic obligations and doxastic voluntarism. In the present paper it is argued that this discussion can benefit from forging links with formal epistemology, namely the combined modal logic of belief, agency, and obligation. A stit-theory-based semantics for deontic doxastic logic is suggested, and it is claimed that this is helpful and illuminating in dealing with the mentioned intricate and important problems from mainstrea…Read more
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52The Power of Belnap: Sequent Systems for SIXTEEN ₃ (review)Journal of Philosophical Logic 39 (4). 2010.The trilattice SIXTEEN₃ is a natural generalization of the wellknown bilattice FOUR₂. Cut-free, sound and complete sequent calculi for truth entailment and falsity entailment in SIXTEEN₃, are presented
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78Contradiction and contrariety. Priest on negationPoznan Studies in the Philosophy of the Sciences and the Humanities 91 (1): 81-93. 2006.Although it is not younger than other areas of non-classical logic, paraconsistent logic has received full recognition only in recent years, largely due to the work of, among others, Newton da Costa, Graham Priest, Diderik Batens, and Jerzy Perzanowski. A logical system Λ is paraconsistent if there is a set of Λ-formulas Δ ∪ {A} such that in Λ one may derive from Δ both A and its negation, and the deductive closure of Δ with respect to Λ is different from the set of all formulas. If from Δ one m…Read more
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Strong Cut-elimination In Display LogicReports on Mathematical Logic 117-131. 1995.It is shown that every displayable propositional logic enjoys strong cut-elimination. This result strengthens Belnap's general cut-elimination theorem for Display Logic.
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42On the methodology of possible worlds semantics. I. Correspondence theoryNotre Dame Journal of Formal Logic 29 (4): 482-496. 1988.
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22A Note On Negation In Categorial GrammarLogic Journal of the IGPL 15 (3): 271-286. 2007.A version of strong negation is introduced into Categorial Grammar. The resulting syntactic calculi turn out to be systems of connexive logic
Areas of Specialization
Epistemology |
Logic and Philosophy of Logic |
Areas of Interest
Philosophy of Language |