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Просмотр по автору "Kalimullin I."

Просмотр по автору "Kalimullin I."

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  • A Hierarchy of Classes of Families and n-Low Degrees 
    Kalimullin I.; Faizrakhmanov M. (2015)
    © 2015, Springer Science+Business Media New York. Presented by the Program Committee of the Conference “Mal’tsev Readings”
  • A survey of results on the d-c.e. and n-c.e. degrees 
    Arslanov M.; Kalimullin I. (2017)
    © Springer International Publishing AG 2017.This paper is a survey on the upper semilattices of Turing and enumeration degrees of n-c.e. sets. Questions on the structural properties of these semilattices, and some ...
  • Algorithmic reducibilities of algebraic structures 
    Kalimullin I. (2012)
    We describe all possible relations between certain reducibities of algebraic structures which are based on the mass problems of structure presentability. © 2010 The Author. Published by Oxford University Press. All rights ...
  • Almost computably enumerable families of sets 
    Kalimullin I. (2008)
    An almost computably enumerable family that is not Ø′- computably enumerable is constructed. Moreover, it is established that for any computably enumerable (c.e.) set A there exists afamily that is X-c.e. if and only if ...
  • Automatic and Polynomial-Time Algebraic Structures 
    Bazhenov N.; Harrison-Trainor M.; Kalimullin I.; Melnikov A.; Ng K. (2019)
    Copyright © The Association for Symbolic Logic 2019. A structure is automatic if its domain, functions, and relations are all regular languages. Using the fact that every automatic structure is decidable, in the literature ...
  • Categoricity Spectra for Rigid Structures 
    Fokina E.; Frolov A.; Kalimullin I. (2016)
    © 2016 by University of Notre Dame. For a computable structure M, the categoricity spectrum is the set of all Turing degrees capable of computing isomorphisms among arbitrary computable copies of M. If the spectrum has a ...
  • Degree spectra and immunity properties 
    Csima B.; Kalimullin I. (2010)
    We analyze the degree spectra of structures in which different types of immunity conditions are encoded. In particular, we give an example of a structure whose degree spectrum coincides with the hyperimmune degrees. As a ...
  • Degree Spectra for Transcendence in Fields 
    Kalimullin I.; Miller R.; Schoutens H. (2019)
    © 2019, Springer Nature Switzerland AG. We show that for both the unary relation of transcendence and the finitary relation of algebraic independence on a field, the degree spectra of these relations may consist of any ...
  • Degrees of categoricity of computable structures 
    Fokina E.; Kalimullin I.; Miller R. (2009)
    Defining the degree of categoricity of a computable structure M to be the least degree d for which M is d-computably categorical, we investigate which Turing degrees can be realized as degrees of categoricity. We show that ...
  • Elementary differences between the (2p)-C. E. and the (2p + 1)-C. E. enumeration degrees 
    Kalimullin I. (2007)
    It is proved that the (2p)-c. e. e-degrees are not elementarily equivalent to the (2p + 1)-c. e. e-degrees for each nonzero p ∈ ω. It follows that m-c. e. e-degrees are not elementarily equivalent to the n-c. e. e-degrees ...
  • Elementary theories and structural properties of d-c.e. and n-c.e. degrees 
    Arslanov M.; Kalimullin I.; Yamaleev M. (2016)
    © 2016, Pleiades Publishing, Ltd.This paper is a survey on the upper semilattices of Turing and enumeration degrees of n-c.e. sets. Questions on the structural properties of these semilattices, and some model-theoretic ...
  • Enumeration degrees and enumerability of familes 
    Kalimullin I. (2009)
    We study the enumerability of families relative to the enumeration degrees. It is shown that if a family of finite sets is e-reducible to every non-zero e-degree, then the family is computably enumerable (c.e). On the ...
  • FOUNDATIONS OF ONLINE STRUCTURE THEORY 
    Bazhenov N.; Downey R.; Kalimullin I.; Melnikov A. (2019)
    Copyright © 2019 The Association for Symbolic Logic. The survey contains a detailed discussion of methods and results in the new emerging area of online punctual structure theory. We also state several open problems.
  • Graphs are not universal for online computability 
    Downey R.; Harrison-Trainor M.; Kalimullin I.; Melnikov A.; Turetsky D. (2020)
    © 2020 Elsevier Inc. We show that structures with only one binary function symbol are universal for “online” (punctual) computable structures. In contrast, we give a description of punctually categorical graphs which implies ...
  • Jump inversions of algebraic structures and Σ-definability 
    Faizrahmanov M.; Kach A.; Kalimullin I.; Montalbán A.; Puzarenko V. (2019)
    © 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim It is proved that for every countable structure A and a computable successor ordinal α there is a countable structure A−α which is (Formula presented.) -least among all ...
  • Limitwise monotonic sequences and degree spectra of structures 
    Kalimullin I.; Khoussainov B.; Melnikov A. (2013)
    In this paper, we study effective monotonic approximations of sets and sequences of sets. We show that there is a sequence of sets which has no uniform computable monotonic approximation but has an x-computable monotonic ...
  • Limitwise monotonic sets of reals 
    Faizrahmanov M.; Kalimullin I. (2015)
    © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. We extend the limitwise monotonicity notion to the case of arbitrary computable linear ordering to get a set which is limitwise monotonic precisely in the non-computable ...
  • Maximality and minimality under limitwise monotonic reducibility 
    Faizrahmanov M.; Kalimullin I.; Zainetdinov D. (2014)
    © 2014, Pleiades Publishing, Ltd. In the paper we study the maximal and minimal objects under Σ-reducibility of the families of the form {ℕ ↾ n: n ∈ A}.
  • On downey's conjecture 
    Arslanov M.; Kalimullin I.; Lempp S. (2010)
    We prove that the degree structures of the d.c.e. and the 3-c.e. Turing degrees are not elementarily equivalent, thus refuting a conjecture of Downey. More specifically, we show that the following statement fails in the ...
  • Online presentations of finitely generated structures 
    Bazhenov N.; Kalimullin I.; Melnikov A.; Ng K.M. (2020)
    © 2020 Elsevier B.V. We systematically investigate into the online content of finitely generated structures. The online content of a potentially infinite algebraic or combinatorial structure is perhaps best reflected by ...

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