University of Groningen Zero-One Laws with Respect to Models Of
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University of Groningen Zero-one laws with respect to models of provability logic and two Grzegorczyk logics Verbrugge, Rineke Published in: Advances in Modal Logic 2018 IMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite from it. Please check the document version below. Document Version Publisher's PDF, also known as Version of record Publication date: 2018 Link to publication in University of Groningen/UMCG research database Citation for published version (APA): Verbrugge, R. (2018). Zero-one laws with respect to models of provability logic and two Grzegorczyk logics. In G. D’Agostino, & G. Bezhanishvilii (Eds.), Advances in Modal Logic 2018: Accepted Short Papers (pp. 115-120) Copyright Other than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons). The publication may also be distributed here under the terms of Article 25fa of the Dutch Copyright Act, indicated by the “Taverne” license. More information can be found on the University of Groningen website: https://www.rug.nl/library/open-access/self-archiving-pure/taverne- amendment. Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim. Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. Download date: 01-10-2021 AiML 2018 Accepted Short Papers ii Contents Rajab Aghamov Modal Logic with the Difference Modality of Topological T_0 -Spaces 1 Paolo Baldi, Petr Cintula and Carles Noguera Translating logics of uncertainty into two-layered modal fuzzy logics . 6 Libor Běhounek and Antonín Dvořák Kripke modalities with truth-functional gaps . 11 Nick Bezhanishvili and Wesley H. Holliday Topological Possibility Frames . 16 Valentin Cassano, Raul Fervari, Carlos Areces and Pablo Cas- tro Interpolation Results for Default Logic Over Modal Logic . 21 Caitlin D’Abrera and Rajeev Goré Verified synthesis of (very simple) Sahlqvist correspondents via Coq . 26 Mirjam de Vos, Barteld Kooi and Rineke Verbrugge Provability logic meets the knower paradox . 31 Sergey Drobyshevich Sorting out FDE-based modal logics . 36 Timo Eckhardt Modeling Forgetting . 41 Éric Goubault, Jérémy Ledent and Sergio Rajsbaum A simplicial complex model for epistemic logic . 46 Giuseppe Greco, Fei Liang, Krishna Manoorkar and Alessandra Palmigiano Proper Display Calculi for Rough Algebras . 51 Christopher Hampson, Stanislav Kikot, Agi Kurucz and Sérgio Marcelino Non-finitely Axiomatisable Modal Products with Infinite Canonical Ax- iomatisations . 56 Alexander Kurz and Bruno Teheux Categories of coalgebras for modal extensions of Łukasiewicz logic . 61 iii Ondrej Majer and Igor Sedlár Plausibility and conditional beliefs in paraconsistent modal logic . 66 George Metcalfe and Olim Tuyt Finite Model Properties for the One-Variable Fragment of First-Order Gödel logic . 71 Luka Mikec and Tin Perkov Existentially valid formulas corresponding to some normal modal logics 76 Grigory Olkhovikov Failure of Interpolation in Stit Logic . 81 Massoud Pourmahdian and Reihane Zoghifard Frame Definability and Extensions of First-Order Modal Logic . 85 Massoud Pourmahdian and Reihane Zoghifard Compactness for Modal Probability Logic . 90 Vít Punčochář and Igor Sedlár Informational semantics for superintuitionistic modal logics . 95 Vít Punčochář and Igor Sedlár From the positive fragment of PDL to its non-classical extensions . 100 Daniel Skurt and Heinrich Wansing Logical Connectives for some FDE-based Modal Logics . 105 Michał M. Stronkowski and Mateusz Uliński Active Structural Completeness for Tabular Modal Logics . 110 Rineke Verbrugge Zero-one laws with respect to models of provability logic and two Grze- gorczyk logics . 115 iv Modal logic with the difference modality of topological T0-spaces Rajab Aghamov 1 Higher School of Economoics 6 Usacheva st., Moscow, 119048 Abstract The aim of this paper is to study the topological modal logic of T0 spaces, with the difference modality. We consider propositional modal logic with two modal operators and [=]. Operator is interpreted as an interior operator and [=] corresponds to 6 6 the inequality relation. We introduce logic S4DT0 and show that S4DT0 is the logic of all T0 spaces and has the finite model property and decidable. Keywords: Kripke sematics, finite model property, completeness, topological semantics 1 Introduction In this paper, apart from we also deal with the difference modality (or modality of inequality) [=], interpreted as true everywhere except here. The expressive power of this6 language in topological spaces has been studied by Gabelaia in [8], where the author presented axiom that defines T0 spaces. For T , where n 1 corresponding logics were known (cf. [3], [8]). We proved the n ≥ completeness of S4DT0 with respect to topological T0-spaces and showed that the logic has finite model property. 2 Preliminary Formulas are constructed in a standard way from a countable set of proposi- tional variables PROP, logical connectives (false) , and one-place modal- ⊥ → ities and [=]. ( , , , , ) are expressed as usual and also 3φ = φ, = φ = [=]6 φ. We∨ ∧ denote¬ > [≡=]A A by [ ]A. ¬ ¬ h6 iThe¬ set6 of¬ all bimodal formulas6 ∧ is called∀ the bimodal language and is de- noted by . ML2 A normal bimodal logic is a subset of formulas L 2 such that 1. L contains all the classical tautologies: ⊆ ML 2. L contains the modal axioms of normality: 1 [email protected] 2 Modal logic with the difference modality of topological T0-spaces (p q) (p q), [=](p →q) →([=]p→ [=]q); 6 → → 6 → 6 3. L is closed with respect to the following inference rules: φ ψ, φ →ψ (MP), φ , φ ( , [=]), φ [=]φ 6 φ → → 6 [ψ/p]φ (Sub). Let L be a logic and Γ be a set of formulas. The minimal logic containing L Γ is denoted by L + Γ. We also write L + ψ instead of L + ψ . ∪In this paper we will use the following axioms: { } (T ) p p, → (4) p p, (D ) [ ]p→ p, ∀ → (BD) p [=] = p, (4 ) [ ]→p 6 [=][h6 =]i p, D ∀ → 6 6 (AT0) (p [=] p = (q [=] q)) ( q = (q p)). We define the∧ 6 following¬ ∧ h6 logics:i ∧ 6 ¬ → ¬ ∨ h6 i ∧ ¬ S4 = K2 + T + 4 S4D = S4 + D + BD + 4D S4DT0 = S4D + AT0 A topological model on a topological space ([6]) X := (X, Ω) is a pair (X,V ), where V : P ROP P (X) (the set of all subsets), i.e. a function that assigns to each propositional→ variable p a set V (p) X and is called a valuation. The ⊆ truth of a formula φ at a point x of a topological model = (X,V ) (notation: , x φ) is defined as usual by induction, particularlyM M , x φ U Ω(x U and y U( , y φ)), M ⇔ ∃ ∈ ∈ ∀ ∈ M , x [=]φ y = x( , y φ). M 6 ⇔ ∀ 6 M Let = (X, Ω,V ) be a topological model and φ be a formula. We say M that φ is true in the model (notation: φ), if it is true at all points of the model, i.e. M M φ x X( , x φ). M ⇔ ∀ ∈ M Let X = (X, Ω) be a topological space, be a class of spaces and φ be a C formula. We say that a formula φ is valid in X (notation: X φ) if it is true in every model on this topological space, i.e. X φ V (X,V φ). ⇔ ∀ We say that the formula φ is valid in if it is valid in every space in . C C Definition 2.1 The logic of a class of topological spaces (denoted by L( )) C C is the set of all formulas in the language 2 that are valid in all spaces of the class . ML C Lemma 2.2 Let X = (X, Ω) be a topological space then X AT0 iff X is a Surname1, Surname2, Surname3, ..., Surname(n-1) and Surname(n) 3 T0-space. Proof. ( ) The proof is by contradiction. Assume that X AT0 and let there be points⇒x and y such that x = y and U Ω( x U y U). Define a valuation V such that V (p) = x6 and V ∀(q) =∈ y . Then∈ ⇔ ∈ { } { } X, V, x p [=] p = (q [=] q) ∧ 6 ¬ ∧ h6 i ∧ 6 ¬ and X, V, x 2 q = (q p). ¬ ∨ h6 i ∧ ¬ This contradicts the fact that X AT0. ( )Assume that X is a T0 space. Let ⇐ X, V, x p [=] p = (q [=] q). ∧ 6 ¬ ∧ h6 i ∧ 6 ¬ Then there is a point y such that y is not equal to x and V (q) = y . Further, at least one of the points x and y is contained in a neighborhood{ that} does not contain the other. That means X, V, x q or X, V, y p which proves our assertion. ¬ ¬ 2 Kripke semantics is well-known (see [1]). We call the logic L complete with respect to the class of topological spaces if L( ) = L. The logic of a class of frames (in notation L( )) is the set ofC formulasC that are valid in all frames from .C For a single frameC F , L(F ) stands for L( F ). A logic L is called KripkeC complete if there exists a class of frames {, such} that L = L( ). A frame F is called an L-frame if L L(F ). C C ⊆ Definition 2.3 Let F = (W, R1, ..., Rn) be a Kripke frame and S∗ be the tran- sitive and reflexive closure of the relation S = ( n R ). For x W, W x i=0 i ∈ y xS∗y (the set of all points reachable from the point x by relation S∗).