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Просмотр по автору "Kalimullin I."

Просмотр по автору "Kalimullin I."

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  • Partial Decidable Presentations in Hyperarithmetic 
    Kalimullin I.; Puzarenko V.; Faizrahmanov M. (2019)
    © 2019, Pleiades Publishing, Inc. We study the problem of the existence of decidable and positive Π11- and Σ11-numberings of the families of Π11- and Σ11-cones with respect to inclusion. Some laws are found that reflect ...
  • Positive Presentations of Families Relative to e-Oracles 
    Kalimullin I.; Puzarenko V.; Faizrahmanov M. (2018)
    © 2018, Pleiades Publishing, Ltd. We introduce the notion of A-numbering which generalizes the classical notion of numbering. All main attributes of classical numberings are carried over to the objects considered here. The ...
  • Primitive Recursive Fields and Categoricity 
    Kalimullin I.; Miller R. (2019)
  • Restrictions on the degree spectra of algebraic structures 
    Kalimullin I. (2008)
    We construct the degree b ≤ 0″ admitting no algebraic structure with degree spectrum {x: x ≰ b}. Moreover, we solve Miller's problem of distinguishing incomparable degrees by the spectra of linear orderings. © Pleiades ...
  • Some notes on degree spectra of the structures 
    Kalimullin I. (2007)
    In the paper the problem of existence of an algebraic structure with the degree spectra {x: x ≮ b} is studied for arbitrary degree b. © Springer-Verlag Berlin Heidelberg 2007.
  • Spectra of algebraic fields and subfields 
    Frolov A.; Kalimullin I.; Miller R. (2009)
    An algebraic field extension of ℚ or ℤ/(p) may be regarded either as a structure in its own right, or as a subfield of its algebraic closure F (either ℚ or ℤ/(p)). We consider the Turing degree spectrum of F in both cases, ...
  • Spectra of degrees of some structures 
    Kalimullin I. (2007)
    We argue for the existence of structures with the spectrum {x : x ≥ a} of degrees, where a is an arbitrary low degree. Also it is stated that there exist structures with the spectrum of degrees, {x : x ≥ a} ⊂ {x : x ≥ b}, ...
  • Spectra of high n and non-low n degrees 
    Frolov A.; Kalimullin I.; Harizanov V.; Kudinov O.; Miller R. (2012)
    We survey known results on spectra of structures and on spectra of relations on computable structures, asking when the set of all highn degrees can be such a spectrum, and likewise for the set of non-low n degrees. We then ...
  • Splitting and nonsplitting in the Σ2 0 enumeration degrees 
    Arslanov M.; Cooper S.; Kalimullin I.; Soskova M. (2011)
    This paper continues the project, initiated in (Arslanov, Cooper and Kalimullin 2003) [3], of describing general conditions under which relative splittings are derivable in the local structure of the enumeration degrees, ...
  • Splitting properties of n-C.E. enumeration degrees 
    Kalimullin I. (2002)
    It is proved that if 1 < m < 2p ≤ n for some integer p then the elementary theories of posets of m-c.e. n-c.e. e-degrees are distinct. It is proved also that the structures 〈D2n ≤ P〉 and 〈D2n ≤ P〉 are not elementary ...
  • The complements of lower cones of degrees and the degree spectra of structures 
    Andrews U.; Cai M.; Kalimullin I.; Lempp S.; Miller J.; Montalbán A. (2016)
    © 2016, Association for Symbolic Logic.We study Turing degrees a for which there is a countable structure A whose degree spectrum is the collection {x: x ≰ a}. In particular, for degrees a from the interval [0ʹ, 0ʺ ], such ...
  • The Diversity of Categoricity Without Delay 
    Kalimullin I.; Melnikov A.; Ng K. (2017)
  • The enumeration spectrum hierarchy of n-families 
    Faizrahmanov M.; Kalimullin I. (2016)
    © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimWe introduce a hierarchy of sets which can be derived from the integers using countable collections. Such families can be coded into countable algebraic structures preserving ...
  • The enumeration spectrum hierarchy of α-families and low<inf>α</inf> degrees 
    Faizrahmanov M.; Kalimullin I. (2016)
    © J.UCS.In this paper we introduce a hierarchy of families which can be derived from the integers using countable collections. This hierarchy coincides with the von Neumann hierarchy of hereditary countable sets in the ...
  • The least Σ-jump inversion theorem for N-families 
    Faizrahmanov M.; Kalimullin I.; Montalbán A.; Puzarenko V. (2017)
    © J.UCS. Studying the Σ-reducibility of families introduced by [Kalimullin and Puzarenko 2009] we show that for every set X ≥ T ∅׳_there is a family of sets F which is the Σ-least countable family whose Σ-jump is Σ-equivalent ...
  • Total degrees and nonsplitting properties of ∑2 0 enumeration degrees 
    Arslanov M.; Cooper S.; Kalimullin I.; Soskova M. (2008)
    This paper continues the project, initiated in [ACK], of describing general conditions under which relative splittings are derivable in the local structure of the enumeration degrees. The main results below include a proof ...
  • Turing and enumeration jumps in the Ershov hierarchy 
    Faizrahmanov M.; Kalimullin I. (2012)
    In the article, we study the behaviour of enumeration jumps of sets of low e-degrees in the Ershov hierarchy. © 2010 The Author. Published by Oxford University Press. All rights reserved.
  • Uniform reducibility of representability problems for algebraic structures 
    Kalimullin I. (2009)
    Given a countable algebraic structure B with no degree we find sufficient conditions for the existence of a countable structure A with the following properties: (1) for every isomorphic copy of A there is an isomorphic ...

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