Kazan Federal University Digital Repository

Browsing by Subject "computably enumerable set"

Browsing by Subject "computably enumerable set"

Sort by: Order: Results:

  • CEA Operators and the Ershov Hierarchy 
    Arslanov M.M.; Batyrshin I.I.; Yamaleev M.M. (2021)
    We examine the relationship between the CEA hierarchy and the Ershov hierarchy within $\Delta_2^0$ Turing degrees. We study the long-standing problem raised in [1] about the existence of a low computably enumerable (c.e.) ...
  • 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 Numberings in Admissible Sets 
    Kalimullin I.S.; Puzarenko V.G.; Faizrahmanov M.K. (2020)
    © 2020, Pleiades Publishing, Ltd. We construct the example of an admissible set A such that there exists a positive computable A-numbering of the family of all A-c.e. sets, whereas any negative computable A-numberings are absent.
  • 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 ...
  • Q-reducibility and m-reducibility on computably enumerable sets 
    Batyrshin I. (2014)
    © 2014, Pleiades Publishing, Ltd. We study the distinctions between Q-reducibility and m-reducibility on computably enumerable sets. We construct a noncomputable m-incomplete computably enumerable set B such that all ...
  • Some Properties of the Upper Semilattice of Computable Families of Computably Enumerable Sets 
    Faizrakhmanov M.K. (2021)
    We look at specific features of the algebraic structure of an upper semilattice of computable families of computably enumerable sets in Ω. It is proved that ideals of minuend and finite families of Ω coincide. We deal with ...
  • Turing Computability: Structural Theory 
    Arslanov M.M.; Yamaleev M.M. (2021)
    In this work, we review results of the last years related to the development of the structural theory of n-c.e. Turing degrees for n > 1. We also discuss possible approaches to solution of the open problems.

Search DSpace

Browse

My Account