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An ‘elementary’ perspective on reasoning about probability spaces
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]. We shall prove that the QPL-theory of the Lebesgue measure on [0, 1] is decidable, and moreover, all atomless spaces have the same QPL-theory. Also we shall introduce the notion of elementary invariant for QPL, and use it to translate the semantics for QPL into the setting of elementary analysis. This will allow us to obtain further decidability results as well as to provide exact complexity upper bounds for a range of interesting undecidable theories.
Yerbolova A. S., Tomashchuk K., Kogan A. et al., Complexity 2026 Vol. 2026 No. 1 Article 5519690
Tis paper presents a novel approach to analyzing and grouping natural languages based on the degree of their chaoticity. It clusters 52 languages from 18 language families, according to the value of the entropy–complexity pair, to reveal the chaotic properties of semantic trajectories. Te obtained clusters appear to be closely correlated with the family of ...
Added: February 16, 2026
Speranski S. O., Journal of Logic and Computation 2013 Vol. 23 No. 5 P. 1035–1055
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
Speranski S. O., Computability 2015 Vol. 4 No. 2 P. 159–174
Added: December 27, 2025
Speranski S. O., Studia Logica 2017 Vol. 105 No. 2 P. 407–429
The paper contains a survey on the complexity of various truth hierarchies arising in Kripke’s theory. I present some new arguments, and use them to obtain a number of interesting generalisations of known results. These arguments are both relatively simple, involving only the basic machinery of constructive ordinals, and very general. ...
Added: December 26, 2025
Speranski S. O., Mathematical Structures in Computer Science 2017 Vol. 27 No. 8 P. 1581–1600
In this article we describe a bunch of probability logics with quantifiers over events, and develop primary techniques for proving computational complexity results (in terms of m-degrees) about these logics, mainly over discrete probability spaces. Also the article contains a comparison with some other probability logics and a discussion of interesting analogies with research in the metamathematics ...
Added: December 26, 2025
Kuznetsov S., Speranski S. O., Annals of Pure and Applied Logic 2022 Vol. 173 No. 2 Article 103057
We introduce infinitary action logic with exponentiation — that is, the multiplicative-additive Lambek calculus extended with Kleene star and with a family of subexponential modalities, which allow some of the structural rules (contraction, weakening, permutation). The logic is presented in the form of an infinitary sequent calculus. We prove cut elimination and, in the case ...
Added: December 26, 2025
Kuznetsov S., Speranski S. O., Studia Logica 2023 Vol. 111 No. 2 P. 251–280
Infinitary action logic can be naturally expanded by adding exponential and subexponential modalities from linear logic. In this article we shall develop infinitary action logic with a subexponential that allows multiplexing (instead of contraction). Both non-commutative and commutative versions of this logic will be considered, presented as infinitary sequent calculi. We shall prove cut admissibility ...
Added: December 26, 2025
Speranski S. O., Izvestiya. Mathematics 2025 Vol. 89 No. 3 P. 193–211
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. 3 Article jzae114
We shall be concerned with two natural expansions of the quantifier-free ‘polynomial’ probability logic of [Fagin et al. 1990]. One of these, denoted by QPL-e, is obtained by adding quantifiers over arbitrary events, and the other, denoted by p-QPL-e, uses quantifiers over propositional formulas — or equivalently, over events expressible by such formulas. The earlier proofs ...
Added: December 26, 2025
LePoire D., Grinin L. E., Korotayev A., Journal of Big History 2025 Vol. 8 No. 3 P. 98–139
Building on foundational work in systems theory, thermodynamics, and evolutionary theory, this paper argues that complexity can serve as a conceptual bridge across disciplines. It explores the role of complexity dynamics in Big History through an integrative theoretical framework that spans physical, chemical, geological, biological, social, cognitive, and civilizational domains. By examining how complexity emerges, ...
Added: November 1, 2025
Yury Semenov, Oleg Sukhoroslov, , in: Mathematical Optimization Theory and Operations Research 24th International Conference, MOTOR 2025, Novosibirsk, Russia, July 7–11, 2025, ProceedingsVol. 15681.: Switzerland: Springer, 2025. P. 317–331.
Added: September 17, 2025
Arzhantsev I., Functional Analysis and Its Applications 1997 Vol. 31 No. 4 P. 278–280
Let a connected reductive group G act on a normal affine variety X with the generic stabilizer H, let the complexity of this action be one, and let the categorial quotient X//G be one-dimensional. Then the closure of any G-orbit in X is normal. ...
Added: June 13, 2025
Cham: Springer, 2020.
This book highlights cutting-edge research in the field of network science, offering scientists, researchers, students, and practitioners a unique update on the latest advances in theory and a multitude of applications. It presents the peer-reviewed proceedings of the Eighth International Conference on Complex Networks and their Applications (COMPLEX NETWORKS 2019), which took place in Lisbon, ...
Added: February 27, 2024
Marina Boykova, Knyazeva H., Salazkin M., Foresight and STI Governance 2023 Vol. 17 No. 4 P. 80–91
The challenges the futures studies face are particularly complex, interconnected, and contradictory, and cannot be resolved using linear approaches. Prognostic science needs tools matching the new contextual complexity, which would allow to capture a much wider range of driving forces, and their potential effects, in a non-linear perspective, to improve the accuracy of forecasts and ...
Added: January 25, 2024
Rybakov M., Shkatov D., Studia Logica 2025 Vol. 113 P. 1–48
In the early 1960s, to prove undecidability of monadic fragments of sublogics of the predicate modal logic QS5 that include the classical predicate logic QCl, Saul Kripke showed how a classical atomic formula with a binary predicate letter can be simulated by a monadic modal formula. We consider adaptations of Kripke's simulation, which we call the Kripke trick, to various modal ...
Added: December 2, 2023
Rybakov M., Shkatov D., Journal of Logic and Computation 2025 Vol. 35 No. 2 Article exad078
We show that the monadic modal logic of a single Kripke frame with finitely many possible worlds, but possibly infinite domains, is decidable. This holds true even for monadic multimodal logics with equality, both if equality interpreted as identity and if equality interpreted as congruence. ...
Added: November 3, 2023
Агаджанян И. А., Rybakov M., Шкатов Д. П., / Series arXiv "math". 2023.
The paper investigates algorithmic complexity of monadic multimodal predicate logics with equality over finite Kripke frames or classes of finite Kripke frames. Precise complexity bounds for monadic logics of classes of Kripke frames with finitely many possible worlds are obtained. ...
Added: July 7, 2023