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Modal logics with transitive closure: Completeness, decidability, filtration
P. 369–388.
Kikot S., Shapirovsky I., Zolin E.
We give a sufficient condition for Kripke completeness of modal logics that have the transitive closure modality. More precisely, we show that if a modal logic admits what we call definable filtration, then its enrichment with the transitive closure modality (and the corresponding axioms) is Kripke complete; in addition, the resulting logic has the finite model property and admits definable filtration, too. This argument can be iterated, and as an application we obtain the finite model property for PDL-like expansions of multimodal logics that admit definable filtration.
Keywords: разрешимостьmodal logicмодальная логикаdecidabilitypropositional dynamic logictransitive closure
Publication based on the results of:
Rybakov M., Annals of Pure and Applied Logic 2026 Vol. 177 No. 10 Article 103811
The paper presents a solution to the question about the decidability of the two-variable fragment of the superintuitionistic predicate logic QLC defined by the class of linear Kripke frames, which is also the ‘superintuitionistic’ fragment of the modal predicate logic QS4.3, under the Gödel translation. We prove that the fragment is undecidable. The result remains true for the ...
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Shehtman V. B., Gagarin A., , in: Graph Games and Logic Design. Recent Developments and Further Directions. (TREN, volume 66)Vol. 66.: Springer, 2026. Ch. 17 P. 419–450.
The chapter contains an overview of results on products of propositional modal logics and related constructions: semiproducts, Segerberg squares, and others. We focus mainly on axiomatizations, finite model property, and decidability; we also sketch connections with classical and modal predicate logics. In some cases we give ideas of proofs, especially of those using games. ...
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Springer, 2026.
This book presents established and new research on the close connections between graph games and systems of logic, particularly existing and newly designed modal logics. The volume utilizes two graph games – the sabotage game and the hide-and-seek game – to demonstrate the natural interplay between designing new graph games and exploring new kinds of ...
Added: June 30, 2026
Speranski S. O., Вестник Новосибирского государственного университета. Серия: Математика, механика, информатика 2011 Т. 11 № 4 С. 78–93
В настоящей статье изучаются вычислительные аспекты формального требования максимальной специфичности, накладываемого на правила в языке пропозициональной классической логики, когда над этим языком задана вычислимая рационально-значная вероятностная мера. Доказана неразрешимость ряда общих проблем по обнаружению максимально специфичных правил и вероятностных мер, для которых совокупность всех специфичных правил вычислима; установлена разрешимость множества максимально специфичных правил при неких ...
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Speranski S. O., Алгебра и логика 2011 Т. 50 № 4 С. 533–546
Язык для рассуждений о вероятности обобщается за счёт добавления в него кванторов по пропозициональным формулам. Далее рассматриваются соответствующие вопросы разрешимости. В частности, представленные результаты демонстрируют неразрешимость проблемы общезначимости для довольно слабого фрагмента нового языка. С другой стороны, устанавливается разрешимость ограниченной проблемы общезначимости для АЕ-предложений. ...
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In the present article, the quantifiers over propositions are first introduced into the language for reasoning about probability, then the complexity issues for validity problems dealing with the corresponding hierarchy of probabilistic sentences are investigated. We prove, among other things, the $\Pi^1_1$-completeness for the general validity and also indicate the least level in the hierarchy ...
Added: December 27, 2025
Speranski S. O., Archive for Mathematical Logic 2013 Vol. 52 No. 5–6 P. 507–516
We carry out a study of definability issues in the standard models of Presburger and Skolem arithmetics (henceforth referred to simply as Presburger and Skolem arithmetics, for short, because we only deal with these models, not the theories, thus there is no risk of confusion) supplied with free unary predicates — which are strongly related to definability in ...
Added: December 27, 2025
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Разрабатывается кванторная версия пропозициональной модальной логики BK из статьи С. П. Одинцова и Х. Вансинга, в основе которой лежит (немодальная) система Белнапа–Данна; мы будем обозначать эту версию через QBK. Сначала с помощью метода канонических моделей будет доказано, что QBK — как и некоторые важные её расширения — сильно полна относительно подходящей семантики возможных миров. Затем мы ...
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Speranski S. O., Izvestiya. Mathematics 2025 Vol. 89 No. 3 P. 609–627
Let QPL-e expand the quantifier-free ‘polynomial’ probability logic of [Fagin et al. 1990] by adding quantifiers over arbitrary events; it can be viewed as a one-sorted elementary language for reasoning about probability spaces. We prove that the $\Sigma_2$-fragment of the QPL-e-theory of finite spaces is hereditarily undecidable. By earlier observations, this implies that $\Pi_2$ is the ...
Added: December 26, 2025
Speranski S. O., Logic Journal of the IGPL 2025 Vol. 33 No. 2 Article jzae042
This paper is concerned with a two-sorted probabilistic language, denoted by QPL, which contains quantifiers over events and over reals, and can be viewed as an elementary language for reasoning about probability spaces. The fragment of QPL containing only quantifiers over reals is a variant of the well-known ‘polynomial’ language from [Fagin et al. 1990, Section 6]. ...
Added: December 26, 2025
Kudinov A., Shapirovsky I., Studia Logica 2025 P. 1–25
We study the finite model property of subframe logics with expressible transitive
reflexive closure modality. For m > 0, let Lm be the logic defined by axiom ♦^{m+1}p →
♦p ∨ p. We construct quotient filtrations for the logics Lm, which implies that these logics
and their tense counterparts have the finite model property. Then, we construct selective
filtrations ...
Added: October 14, 2025
Kudinov A., Мясников К. М., Математика и теоретические компьютерные науки 2025 Т. 3 № 2 С. 58–84
The paper proves that for weakly transitive logics with the universal modality, whose formula satisfiability problem is in PSPACE, adding the connectedness axiom does not increase the complexity. Furthermore, an explicit algorithm solving this problem is presented. ...
Added: October 14, 2025