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Просмотр по автору "Frolov A."

Просмотр по автору "Frolov A."

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  • A note on Δ 2 0 -Spectra of linear orderings and degree spectra of the successor relation 
    Frolov A. (2013)
    In this paper we construct linear orderings whoseΔ 2 0 -spectra coincide with classes of all high0 and high1 degrees, respectively. We also prove that there exists a computable linear ordering such that its degree spectrum ...
  • 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 ...
  • Computability on linear orderings enriched with predicates 
    Alaev P.; Thurber J.; Frolov A. (2009)
    Let L be a quasidiscrete linear ordering. We specify some conditions for the existence of a computable presentation for L or for the structure (L, adj), where adj(x, y) is a predicate distinguishing adjacent elements. © ...
  • Degree spectra of the successor relation of computable linear orderings 
    Chubb J.; Frolov A.; Harizanov V. (2009)
    We establish that for every computably enumerable (c.e.) Turing degree b the upper cone of c.e. Turing degrees determined by b is the degree spectrum of the successor relation of some computable linear ordering. This follows ...
  • Early to Middle Jurassic history of the southern Siberian continent (Transbaikalia) recorded in sediments of the Siberian Craton: Sm-Nd and U-Pb provenance study 
    Demonterova E.; Ivanov A.; Mikheeva E.; Arzhannikova A.; Frolov A.; Arzannikov S.; Bryanskiy N.; Pavlova L. (2017)
    © SGF, Published by EDP Sciences 2017. The deposition of Jurassic continental sedimentary rocks in the southern part of the Siberian continent (Transbaikalia) reflects the intensification of tectonomagmatic processes in ...
  • Generalized modes of optical fiber 
    Frolov A.; Kartchevskiy E. (2011)
    The eigenvalue problem for generalized natural modes of an inhomogeneous optical fiber is formulated as a problem for Helmholtz equation with Reichardt condition at infinity in the cross-sectional plane. The generalized ...
  • Increasing η-representable degrees 
    Frolov A.; Zubkov M. (2009)
    In this paper we prove that any Δ0 3 degree has an increasing η-representation. Therefore, there is an increasing η-representable set without a strong η-representation. © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
  • Integral Equation Methods in Optical Waveguide Theory 
    Frolov A.; Kartchevskiy E. (2013)
    Optical waveguides are regular dielectric rods having various cross-sectional shapes where generally the permittivity may vary in the waveguide's cross section. The permittivity of the surrounding medium may be a step-index ...
  • Limitwise monotonic functions relative to the Kleene’s Ordinal Notation System 
    Frolov A.; Zubkov M. (2014)
    © 2014, Pleiades Publishing, Ltd. In this paper we generalize the theorem that previously obtained by the authors for a wider class of linear orders using X-limitwise monotonic functions relative to the Kleene’s Ordinal ...
  • Linear Orderings of Low Degree 
    Frolov A. (2010)
    We consider the class of so-called k-quasidiscrete linear orderings, show that every k-quasi-discrete ordering of low degree has a computable representation, and study estimates for the complexity of all isomorphisms ...
  • Low linear orderings 
    Frolov A. (2012)
    We say that L is weakly η-like if L/∼ is isomorphic to the natural ordering of rational numbers. We construct a computable presentation of any low weakly η-like linear ordering with no strongly η-like interval. Also we ...
  • Natural modes of weakly guiding optical fiber 
    Frolov A.; Karchevskiy E. (2010)
    The eigenvalue problem for generalized natural modes of an inhomogeneous optical fiber is formulated as a problem for the Helmholtz equation with Reichardt condition at infinity in the cross-sectional plane. The generalized ...
  • Presentations of the successor relation of computable linear ordering 
    Frolov A. (2010)
    We prove that a nontrivial degree spectrum of the successor relation of either strongly η-like or non-η-like computable linear orderings is closed upwards in the class of all computably enumerable degrees. We also show ...
  • Provenance change in the Irkutsk coal basin during the early and middle Jurassic: Geochemical and Sm-Nd isotope evidence 
    Mikheeva E.; Demonterova E.; Frolov A.; Arzhannikova A.; Arzhannikov S.; Cherkashina T.; Ivanov A. (2017)
    © 2017, Pleiades Publishing, Ltd. On the basis of the recently accepted chronostratigraphic chart, Jurassic sedimentation in the Irkutsk coal basin took place over a short time interval (~23 My), from the Pliensbachian ...
  • Provision of gas engine bus performance with air-fuel mixture 
    Kulakov A.; Gattarov I.; Frolov A. (2015)
    © 2015, ASERS Publishing House. All rights reserved. To evaluate air ratio impact on the engine temperature condition, environmental and economic performance, in-operation and bench test of gas engines with an exhaust gas ...
  • Ranges of η-functions of η-like linear orderings 
    Frolov A. (2012)
    We completely describe ranges of η-functions of η-like linear orderings without computable presentations. © 2012 Allerton Press, Inc.
  • Scattered linear orderings with no computable presentation 
    Frolov A. (2014)
    In this paper we construct a low2 scattered linear orderings with no computable presentation. This is a negative answer for the question of A. Kach and A. Montalbán. © 2014 Pleiades Publishing, Ltd.
  • 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 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 ...
  • Strong jump inversion 
    Calvert W.; Frolov A.; Harizanov V.; Knight J.; McCoy C.; Soskova A.; Vatev S. (2018)
    © The Author(s) 2018. We say that a structure A admits strong jump inversion provided that for every oracle X, if X' computes D(C)'for some C ≅ A, then X computes D(B) for some B ≅ A. Jockusch and Soare (1991, APAL, 52, ...

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