
2On Nontransitive “Identity”In Can Başkent & Thomas Macaulay Ferguson (eds.), Graham Priest on Dialetheism and Paraconsistency, Springer Verlag. pp. 535553. 2019.Graham Priest takes the relation of identity to be nontransitive. In this paper, we are going to discuss several consequences of identity as a nontransitive relation. We will consider the Henkinstyle completeness proof for classical firstorder logic with a nontransitive “identity” predicate, Leibnizidentity in Priest’s secondorder minimal logic of paradox, and the question whether or not identity of individuals should be defined as Leibnizidentity.

34Routley Star and HyperintensionalityJournal of Philosophical Logic 50 (1): 3356. 2021.We compare the logic HYPE recently suggested by H. Leitgeb as a basic propositional logic to deal with hyperintensional contexts and HeytingOckham logic introduced in the course of studying logical aspects of the wellfounded semantics for logic programs with negation. The semantics of HeytingOckham logic makes use of the socalled Routley star negation. It is shown how the Routley star negation can be obtained from Dimiter Vakarelov’s theory of negation and that propositional HYPE coincides w…Read more

6Correction to: The nature of entailment: an informational approachSynthese 12. forthcoming.The paragraph starting with “By accepting condition only,...” should be read as follows

7New Essays on BelnapDunn Logic (edited book)Springer Verlag. 2019.This edited volume collects essays on the fourvalued logic known as BelnapDunn logic, or firstdegree entailment logic. It also looks at various formal systems closely related to it. These include the strong Kleene logic and the Logic of Paradox. Inside, readers will find reprints of seminal papers written by the fathers of the field: Nuel Belnap and Michael Dunn. In addition, the collection also features a wellknown but previously unpublished manuscript of Dunn, an interview with Belnap, and…Read more

2Proofs, Disproofs, and Their DualsIn Marcus Kracht, Maarten de Rijke, Heinrich Wansing & Michael Zakharyaschev (eds.), Advances in Modal Logic, Csli Publications. pp. 483505. 2010.

Tableaux for multiagent deliberativestit logicIn Marcus Kracht, Maarten de Rijke, Heinrich Wansing & Michael Zakharyaschev (eds.), Advances in Modal Logic, Csli Publications. pp. 503520. 2006.

1Connexive Modal LogicIn Marcus Kracht, Maarten de Rijke, Heinrich Wansing & Michael Zakharyaschev (eds.), Advances in Modal Logic, Csli Publications. pp. 367383. 2005.

32Connexive logics. An overview and current trendsLogic and Logical Philosophy 1. forthcoming.In this introduction, we offer an overview of main systems developed in the growing literature on connexive logic, and also point to a few topics that seem to be collecting attention of many of those interested in connexive logic. We will also make clear the context to which the papers in this special issue belong and contribute.

17Proof systems for various fdebased modal logicsReview of Symbolic Logic 13 (4): 720747. 2020.We present novel proof systems for various FDEbased modal logics. Among the systems considered are a number of Belnapian modal logics introduced in Odintsov & Wansing and Odintsov & Wansing, as well as the modal logic KN4 with strong implication introduced in Goble. In particular, we provide a Hilbertstyle axiom system for the logic $BK^{\square  } $ and characterize the logic BK as an axiomatic extension of the system $BK^{FS} $. For KN4 we provide both an FDEstyle axiom system and a decida…Read more

1Dag Prawitz on Proofs and Meaning (edited book)Springer. 2014.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 inferencebased meaning theories have been extremely influential in the development of modern proof theory and antirealistic 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

12Nino B. Cocchiarella and Max A. Freund. Modal logic. An introduction to its syntax and semantics. Oxford University Press, Oxford, 2008, xi + 268 pp (review)Bulletin of Symbolic Logic 16 (2): 275276. 2010.

16On Definability of Connectives and Modal Logics over FDELogic and Logical Philosophy 1. forthcoming.

10Simplified Tableaux for STIT Imagination LogicJournal of Philosophical Logic 48 (6): 9811001. 2019.We show how to correct the analytic tableaux system from the paper Olkhovikov and Wansing, 259–279, 2018).

On Split Negation, Strong Negation, Information, Falsification, and VerificationIn Katalin Bimbó (ed.), J. Michael Dunn on Information Based Logics, Springer. 2016.

4Inference as doxastic agency. Part II: Ramifications and refinementsAustralasian Journal of Logic 14 (4): 408438. 2017.Justification stit logic is a logic for reasoning about proving as a certain kind of activity, namely seeing to it that a proof is publicly available. It merges the semantical analysis of deliberatively seeingtoitthat from stit theory and the semantics of the epistemic logic with justification from. In this paper, after recalling its language and basic semantical definitions, various ramifications and refinements of justification stit logic are presented and discussed: imposing natural restri…Read more

10Negation as Cancellation, Connexive Logic, and qLPmAustralasian Journal of Logic 15 (2): 476488. 2018.In this paper, we shall consider the socalled cancellation view of negation and the inferential role of contradictions. We will discuss some of the problematic aspects of negation as cancellation, such as its original presentation by Richard and Valery Routley and its role in motivating connexive logic. Furthermore, we will show that the idea of inferential ineffectiveness of contradictions can be conceptually separated from the cancellation model of negation by developing a system we call qLPm…Read more

6Proofs, Disproofs, and Their DualsIn Lev Beklemishev, Valentin Goranko & Valentin Shehtman (eds.), Advances in Modal Logic, Volume 8, Csli Publications. pp. 483505. 2010.

9Tableaux for multiagent deliberativestit logicIn Guido Governatori, Ian Hodkinson & Yde Venema (eds.), Advances in Modal Logic, Volume 6, Csli Publications. pp. 503520. 2006.

5Connexive Modal LogicIn Renate Schmidt, Ian PrattHartmann, Mark Reynolds & Heinrich Wansing (eds.), Advances in Modal Logic, Volume 5, Csli Publications. pp. 367383. 2005.

28Inference as Doxastic Agency. Part I: The Basics of Justification Stit LogicStudia Logica 107 (1): 167194. 2019.In this paper we consider logical inference as an activity that results in proofs and hence produces knowledge. We suggest to merge the semantical analysis of deliberatively seeingtoitthat from stit theory and the semantics of the epistemic logic with justification from. The general idea is to understand proving that A as seeing to it that a proof of A is available. We introduce a semantics of various notions of proving as an activity and present a number of valid principles that relate the v…Read more

18Disentangling FDE Based Paraconsistent Modal LogicsStudia Logica 105 (6): 12211254. 2017.The relationships between various modal logics based on Belnap and Dunn’s paraconsistent fourvalued 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

23Kripke Completeness of Biintuitionistic Multilattice Logic and its Connexive VariantStudia Logica 105 (6): 11931219. 2017.In this paper, biintuitionistic multilattice logic, which is a combination of multilattice logic and the biintuitionistic logic also known as Heyting–Brouwer logic, is introduced as a Gentzentype sequent calculus. A Kripke semantics is developed for this logic, and the completeness theorem with respect to this semantics is proved via theorems for embedding this logic into biintuitionistic logic. The logic proposed is an extension of firstdegree entailment logic and can be regarded as a bii…Read more

This volume comprises the proceedings of the First AllBerlin Workshop on Nonclassical Logics and Information Processing, held at the Free University of Berlin, November 910, 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 l…Read more

35Proof 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.
Areas of Specialization
Epistemology 
Logic and Philosophy of Logic 
Areas of Interest
Philosophy of Language 