scholarly journals Efficient Local Reductions to Basic Modal Logic

2021 ◽  
pp. 76-92
Author(s):  
Fabio Papacchini ◽  
Cláudia Nalon ◽  
Ullrich Hustadt ◽  
Clare Dixon
Keyword(s):  
Normal Form ◽  
Modal Logic ◽  
Modal Logics ◽  
First Order ◽  
Local Reasoning ◽  
Resolution Calculus

AbstractWe present novel reductions of the propositional modal logics "Image missing" , "Image missing" , "Image missing" , "Image missing" and "Image missing" to Separated Normal Form with Sets of Modal Levels. The reductions result in smaller formulae than the well-known reductions by Kracht and allow us to use the local reasoning of the prover "Image missing" to determine the satisfiability of modal formulae in these logics. We show experimentally that the combination of our reductions with the prover "Image missing" performs well when compared with a specialised resolution calculus for these logics and with the b̆uilt-in reductions of the first-order prover SPASS.

scholarly journals Recursive enumerability and elementary frame definability in predicate modal logic

2019 ◽  
Vol 30 (2) ◽  
pp. 549-560 ◽  
Author(s):  
Mikhail Rybakov ◽  
Dmitry Shkatov
Keyword(s):  
Modal Logic ◽  
Modal Logics ◽  
The Other ◽  
Kripke Semantics ◽  
First Order ◽  
Elementary Class ◽  
Recursive Enumerability ◽  
Kripke Frames ◽  
Recursively Enumerable ◽  
The Relationship

Abstract We investigate the relationship between recursive enumerability and elementary frame definability in first-order predicate modal logic. On one hand, it is well known that every first-order predicate modal logic complete with respect to an elementary class of Kripke frames, i.e. a class of frames definable by a classical first-order formula, is recursively enumerable. On the other, numerous examples are known of predicate modal logics, based on ‘natural’ propositional modal logics with essentially second-order Kripke semantics, that are either not recursively enumerable or Kripke incomplete. This raises the question of whether every Kripke complete, recursively enumerable predicate modal logic can be characterized by an elementary class of Kripke frames. We answer this question in the negative, by constructing a normal predicate modal logic which is Kripke complete, recursively enumerable, but not complete with respect to an elementary class of frames. We also present an example of a normal predicate modal logic that is recursively enumerable, Kripke complete, and not complete with respect to an elementary class of rooted frames, but is complete with respect to an elementary class of frames that are not rooted.

scholarly journals Constructive interpolation in hybrid logic

2003 ◽  
Vol 68 (2) ◽  
pp. 463-480 ◽  
Author(s):  
Patrick Blackburn ◽  
Maarten Marx
Keyword(s):  
Modal Logic ◽  
Strong Evidence ◽  
Interpolation Property ◽  
Modal Logics ◽  
Hybrid Logic ◽  
Basic Algorithm ◽  
Technical Problems ◽  
First Order ◽  
Elementary Class ◽  
Interpolation Algorithms

AbstractCraig's interpolation lemma (if φ → ψ is valid, then φ → θ and θ → ψ are valid, for θ a formula constructed using only primitive symbols which occur both in φ and ψ) fails for many propositional and first order modal logics. The interpolation property is often regarded as a sign of well-matched syntax and semantics. Hybrid logicians claim that modal logic is missing important syntactic machinery, namely tools for referring to worlds, and that adding such machinery solves many technical problems. The paper presents strong evidence for this claim by defining interpolation algorithms for both propositional and first order hybrid logic. These algorithms produce interpolants for the hybrid logic of every elementary class of frames satisfying the property that a frame is in the class if and only if all its point-generated subframes are in the class. In addition, on the class of all frames, the basic algorithm is conservative: on purely modal input it computes interpolants in which the hybrid syntactic machinery does not occur.

Comments on Robert Goldblatt’s “Fine’s Theorem on First-Order Complete Modal Logics”

2020 ◽  
pp. 482-484
Author(s):  
Kit Fine
Keyword(s):  
Modal Logic ◽  
Modal Logics ◽  
First Order

I am grateful to Robert Goldblatt for his lucid and masterly chapter on “canonicity” in modal logic. The main result of Fine 1975a was that a modal logic being first-order complete (i.e. complete for a first-order class of frames) was sufficient for the logic to be canonical, i.e. for its canonical frames to be frames for the logic. But ideally what one would like is an equivalence. ...

scholarly journals Undecidability of First-Order Intuitionistic and Modal Logics with Two variables

2005 ◽  
Vol 11 (3) ◽  
pp. 428-438 ◽  
Author(s):  
Roman Kontchakov ◽  
Agi Kurucz ◽  
Michael Zakharyaschev
Keyword(s):  
Modal Logic ◽  
Intuitionistic Logic ◽  
Modal Logics ◽  
Kripke Frame ◽  
Standard Nomenclature ◽  
Quantified Modal Logic ◽  
First Order

AbstractWe prove that the two-variable fragment of first-order intuitionistic logic is undecidable, even without constants and equality. We also show that the two-variable fragment of a quantified modal logic L with expanding first-order domains is undecidable whenever there is a Kripke frame for L with a point having infinitely many successors (such are, in particular, the first-order extensions of practically all standard modal logics like K, K4, GL, S4, S5, K4.1, S4.2, GL.3, etc.). For many quantified modal logics, including those in the standard nomenclature above, even the monadic two-variable fragments turn out to be undecidable.

scholarly journals Coalescing: Syntactic Abstraction for Reasoning in First-Order Modal Logics

10.29007/cpbz ◽  
2018 ◽  
Author(s):  
Damien Doligez ◽  
Jael Kriener ◽  
Leslie Lamport ◽  
Tomer Libal ◽  
Stephan Merz
Keyword(s):  
Modal Logic ◽  
Modal Logics ◽  
Order Logic ◽  
First Order Logic ◽  
First Order ◽  
Propositional Modal Logic ◽  
Theorem Provers ◽  
Syntactic Abstraction

We present a syntactic abstraction method to reason about first-order modal logics by using theorem provers for standard first-order logic and for propositional modal logic.

scholarly journals Fine’s Theorem on First-Order Complete Modal Logics

2020 ◽  
pp. 316-334
Author(s):  
Robert Goldblatt
Keyword(s):  
Modal Logic ◽  
Modal Logics ◽  
Modal Algebra ◽  
First Order ◽  
Kripke Frames ◽  
Canonical Frame ◽  
History Of ◽  
Order Completeness

Fine’s influential Canonicity Theorem states that if a modal logic is determined by a first-order definable class of Kripke frames, then it is valid in its canonical frames. This article reviews the background and context of this result, and the history of its impact on further research. It then develops a new characterization of when a logic is canonically valid, providing a precise point of distinction with the property of first-order completeness. The ultimate point is that the construction of the canonical frame of a modal algebra does not commute with the ultrapower construction.

On formalizing the distinction between logical and factual truth

1966 ◽  
Vol 31 (3) ◽  
pp. 460-477
Author(s):  
William H. Hanson
Keyword(s):  
Modal Logic ◽  
Propositional Logic ◽  
Modal Logics ◽  
Order Logic ◽  
First Order Logic ◽  
First Order ◽  
Feature Section

Semantical systems that distinguish between logically true and factually true formulas are well-known from the work of Carnap. The present paper is concerned with extending the formalization of this distinction in two ways. First, we show how to construct syntactical (i.e., logistic) systems that correspond to semantical systems of the type just mentioned. Such a syntactical system for propositional logic is developed in section 3. Similar systems for first-order logic are sketched in section 5. Second, we show how to extend semantical systems that make the logical-factual distinction to languages containing modal connectives. Carnap's work on modal logic conspicuously lacks this feature. Section 4 contains such semantical systems for four well-known modal logics. It also contains a syntactical equivalent of one of these modal semantical systems.

scholarly journals Extensions in graph normal form

2020 ◽  
Author(s):  
Michał Walicki
Keyword(s):  
Normal Form ◽  
Fixed Points ◽  
Propositional Logic ◽  
Order Logic ◽  
First Order Logic ◽  
First Order ◽  
Special Cases

Abstract Graph normal form, introduced earlier for propositional logic, is shown to be a normal form also for first-order logic. It allows to view syntax of theories as digraphs, while their semantics as kernels of these digraphs. Graphs are particularly well suited for studying circularity, and we provide some general means for verifying that circular or apparently circular extensions are conservative. Traditional syntactic means of ensuring conservativity, like definitional extensions or positive occurrences guaranteeing exsitence of fixed points, emerge as special cases.

scholarly journals Formula size games for modal logic and μ-calculus

2019 ◽  
Vol 29 (8) ◽  
pp. 1311-1344 ◽  
Author(s):  
Lauri T Hella ◽  
Miikka S Vilander
Keyword(s):  
Modal Logic ◽  
Optimal Strategy ◽  
Order Logic ◽  
First Order Logic ◽  
Kripke Models ◽  
First Order ◽  
Modal Operators ◽  
Crucial Difference ◽  
Definition Of ◽  
Person Game

Abstract We propose a new version of formula size game for modal logic. The game characterizes the equivalence of pointed Kripke models up to formulas of given numbers of modal operators and binary connectives. Our game is similar to the well-known Adler–Immerman game. However, due to a crucial difference in the definition of positions of the game, its winning condition is simpler, and the second player does not have a trivial optimal strategy. Thus, unlike the Adler–Immerman game, our game is a genuine two-person game. We illustrate the use of the game by proving a non-elementary succinctness gap between bisimulation invariant first-order logic $\textrm{FO}$ and (basic) modal logic $\textrm{ML}$. We also present a version of the game for the modal $\mu $-calculus $\textrm{L}_\mu $ and show that $\textrm{FO}$ is also non-elementarily more succinct than $\textrm{L}_\mu $.

A Modal Semantics of Negation in Logic Programming

1992 ◽  
Vol 16 (3-4) ◽  
pp. 231-262
Author(s):  
Philippe Balbiani
Keyword(s):  
Modal Logic ◽  
Logic Programming ◽  
Modal Logics ◽  
Kripke Models ◽  
Logic Programs ◽  
Modal Semantics ◽  
Soundness And Completeness ◽  
Modal Completion ◽  
Well Foundedness

The beauty of modal logics and their interest lie in their ability to represent such different intensional concepts as knowledge, time, obligation, provability in arithmetic, … according to the properties satisfied by the accessibility relations of their Kripke models (transitivity, reflexivity, symmetry, well-foundedness, …). The purpose of this paper is to study the ability of modal logics to represent the concepts of provability and unprovability in logic programming. The use of modal logic to study the semantics of logic programming with negation is defended with the help of a modal completion formula. This formula is a modal translation of Clack’s formula. It gives soundness and completeness proofs for the negation as failure rule. It offers a formal characterization of unprovability in logic programs. It characterizes as well its stratified semantics.

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