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37
Derivation rules as antiaxioms in modal logic
 Journal of Symbolic Logic
, 1993
"... Abstract. We discuss a ‘negative ’ way of defining frame classes in (multi)modal logic, and address the question whether these classes can be axiomatized by derivation rules, the ‘nonξ rules’, styled after Gabbay’s Irreflexivity Rule. The main result of this paper is a metatheorem on completeness ..."
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Cited by 45 (4 self)
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Abstract. We discuss a ‘negative ’ way of defining frame classes in (multi)modal logic, and address the question whether these classes can be axiomatized by derivation rules, the ‘nonξ rules’, styled after Gabbay’s Irreflexivity Rule. The main result of this paper is a metatheorem on completeness, of the following kind: If Λ is a derivation system having a set of axioms that are special Sahlqvist formulas, and Λ+ is the extension of Λ with a set of nonξ rules, then Λ+ is strongly sound and complete with respect to the class of frames determined by the axioms and the rules.
Labelled Propositional Modal Logics: Theory and Practice
, 1996
"... We show how labelled deductive systems can be combined with a logical framework to provide a natural deduction implementation of a large and wellknown class of propositional modal logics (including K, D, T , B, S4, S4:2, KD45, S5). Our approach is modular and based on a separation between a base lo ..."
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Cited by 40 (8 self)
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We show how labelled deductive systems can be combined with a logical framework to provide a natural deduction implementation of a large and wellknown class of propositional modal logics (including K, D, T , B, S4, S4:2, KD45, S5). Our approach is modular and based on a separation between a base logic and a labelling algebra, which interact through a fixed interface. While the base logic stays fixed, different modal logics are generated by plugging in appropriate algebras. This leads to a hierarchical structuring of modal logics with inheritance of theorems. Moreover, it allows modular correctness proofs, both with respect to soundness and completeness for semantics, and faithfulness and adequacy of the implementation. We also investigate the tradeoffs in possible labelled presentations: We show that a narrow interface between the base logic and the labelling algebra supports modularity and provides an attractive prooftheory (in comparision to, e.g., semantic embedding) but limits th...
Back and Forth Between Modal Logic and Classical Logic
, 1994
"... Model Theory. That is, we have a nonempty family I of partial isomorphisms between two models M and N, which is closed under taking restrictions to smaller domains, and where the standard BackandForth properties are now restricted to apply only to partial isomorphisms of size at most k. Proof. ..."
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Cited by 34 (3 self)
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Model Theory. That is, we have a nonempty family I of partial isomorphisms between two models M and N, which is closed under taking restrictions to smaller domains, and where the standard BackandForth properties are now restricted to apply only to partial isomorphisms of size at most k. Proof. (A complete argument is in [16].) An outline is reproduced here, for convenience. First, kvariable formulas are preserved under partial isomorphism, by a simple induction. More precisely, one proves, for any assignment A and any partial isomorphism I 2 I which is defined on the Avalues for all variables x 1 ; : : : ; x k , that M;A j= OE iff N; I ffi A j= OE: The crucial step in the induction is the quantifier case. Quantified variables are irrelevant to the assignment, so that the relevant partial isomorphism can be restricted to size at most k \Gamma 1, whence a matching choice for the witness can be made on the opposite side. This proves "only if". Next, "if" has a proof analogous to...
Modal Logic, Transition Systems and Processes
, 1994
"... Transition systems can be viewed either as process diagrams or as Kripke structures. The first perspective is that of process theory, the second that of modal logic. This paper shows how various formalisms of modal logic can be brought to bear on processes. Notions of bisimulation can not only be mo ..."
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Cited by 22 (3 self)
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Transition systems can be viewed either as process diagrams or as Kripke structures. The first perspective is that of process theory, the second that of modal logic. This paper shows how various formalisms of modal logic can be brought to bear on processes. Notions of bisimulation can not only be motivated by operations on transition systems, but they can also be suggested by investigations of modal formalisms. To show that the equational view of processes from process algebra is closely related to modal logic, we consider various ways of looking at the relation between the calculus of basic process algebra and propositional dynamic logic. More concretely, the paper contains preservation results for various bisimulation notions, a result on the expressive power of propositional dynamic logic, and a definition of bisimulation which is the proper notion of invariance for concurrent propositional dynamic logic. Keywords: modal logic, transition systems, bisimulation, process algebra 1 In...
Monotonic Modal Logics
, 2003
"... Monotonic modal logics form a generalization of normal modal logics... ..."
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Cited by 22 (0 self)
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Monotonic modal logics form a generalization of normal modal logics...
Undecidability of Compass Logic
 JOURNAL OF LOGIC AND COMPUTATION
, 1997
"... It is known that the tiling technique can be used to give simple proofs of undecidability of various twodimensional modal and temporal logics. However, up until now, the simplest twodimensional temporal logic, the compass logic of Venema, has eluded such treatment. We present a new coding of an en ..."
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Cited by 21 (1 self)
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It is known that the tiling technique can be used to give simple proofs of undecidability of various twodimensional modal and temporal logics. However, up until now, the simplest twodimensional temporal logic, the compass logic of Venema, has eluded such treatment. We present a new coding of an enumeration of the tiling plane which enables us to show that the compass logic is undecidable.
Tableaux for Quantified Hybrid Logic
 METHODS FOR MODALITIES 2, WORKSHOP PROCEEDINGS, NOVEMBER 2930, 2001. ILLC
, 2002
"... We present a (sound and complete) tableau calculus for Quantified Hybrid Logic (QHL). QHL is an extension of orthodox quantified modal logic: as well as the usual # and # modalities it contains names for (and variables over) states, operators @s for asserting that a formula holds at a named state ..."
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We present a (sound and complete) tableau calculus for Quantified Hybrid Logic (QHL). QHL is an extension of orthodox quantified modal logic: as well as the usual # and # modalities it contains names for (and variables over) states, operators @s for asserting that a formula holds at a named state, and a binder that binds a variable to the current state. The firstorder component contains equality and rigid and non rigid designators. As far as we are aware, ours is the first tableau system for QHL. Completeness
Cutfree Display Calculi for Nominal Tense Logics
 Conference on Tableaux Calculi and Related Methods (TABLEAUX
, 1998
"... . We define cutfree display calculi for nominal tense logics extending the minimal nominal tense logic (MNTL) by addition of primitive axioms. To do so, we use a translation of MNTL into the minimal tense logic of inequality (MTL 6= ) which is known to be properly displayable by application of Krac ..."
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Cited by 17 (7 self)
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. We define cutfree display calculi for nominal tense logics extending the minimal nominal tense logic (MNTL) by addition of primitive axioms. To do so, we use a translation of MNTL into the minimal tense logic of inequality (MTL 6= ) which is known to be properly displayable by application of Kracht's results. The rules of the display calculus ffiMNTL for MNTL mimic those of the display calculus ffiMTL 6= for MTL 6= . Since ffiMNTL does not satisfy Belnap's condition (C8), we extend Wansing's strong normalisation theorem to get a similar theorem for any extension of ffiMNTL by addition of structural rules satisfying Belnap's conditions (C2)(C7). Finally, we show a weak Sahlqviststyle theorem for extensions of MNTL, and by Kracht's techniques, deduce that these Sahlqvist extensions of ffiMNTL also admit cutfree display calculi. 1 Introduction Background: The addition of names (also called nominals) to modal logics has been investigated recently with different motivations; see...
Counterfactuals and Updates as Inverse Modalities
 Journal of Logic, Language and Information
, 1997
"... . We point out a simple but hitherto ignored link between the theory of updates and counterfactuals and classical modal logic: update is a classical existential modality, counterfactual is a classical universal modality, and the accessibility relations corresponding to these modalities are inverses. ..."
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. We point out a simple but hitherto ignored link between the theory of updates and counterfactuals and classical modal logic: update is a classical existential modality, counterfactual is a classical universal modality, and the accessibility relations corresponding to these modalities are inverses. The Ramsey Rule (often thought esoteric) is simply an axiomatisation of this inverse relationship. We use this fact to translate between postulates for updates and postulates for counterfactuals. Thus, Katsuno/Mendelzon's postulates U1U8 are translated into counterfactual postulates C1C8 (table VII), and many of the familiar counterfactual postulates are translated into postulates for updates (table VIII). Our conclusions are summarised in table V. We also present a syntactic condition which is sufficient to guarantee that a translation from update to counterfactual (or vice versa) is possible. 1. Introduction Background. An intuitive connection between theory change and counterfactuals...
Duality and Canonical Extensions of Bounded Distributive Lattices with Operators, and Applications to the Semantics of NonClassical Logics I
 Studia Logica
, 1998
"... The main goal of this paper is to explain the link between the algebraic and the Kripkestyle models for certain classes of propositional logics. We start by presenting a Priestleytype duality for distributive lattices endowed with a general class of wellbehaved operators. We then show that fin ..."
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Cited by 16 (6 self)
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The main goal of this paper is to explain the link between the algebraic and the Kripkestyle models for certain classes of propositional logics. We start by presenting a Priestleytype duality for distributive lattices endowed with a general class of wellbehaved operators. We then show that finitelygenerated varieties of distributive lattices with operators are closed under canonical embedding algebras. The results are used in the second part of the paper to construct topological and nontopological Kripkestyle models for logics that are sound and complete with respect to varieties of distributive lattices with operators in the abovementioned classes. Introduction In the study of nonclassical propositional logics (and especially of modal logics) there are two main ways of defining interpretations or models. One possibility is to use algebras  usually lattices with operators  as models. Propositional variables are interpreted over elements of these algebraic models, an...