On Universal Pairs in the Ershov Hierarchy


Bazhenov N.A. Mustafa M. Ospichev S.S.
January 2021Pleiades journals

Siberian Mathematical Journal
2021#62Issue 123 - 31 pp.

We develop the Ershov theory of C-classes for some finite families of sets in the Ershovhierarchy. We generalize the result by Muchnik on multiple$ m $-reducibility as follows: There exists an $ m $-universal pair of disjoint setsfor each level of the Ershov hierarchy.

$ m $-reducibility , 510.55 , C-class , computable numbering , Ershov hierarchy

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Sobolev Institute of Mathematics, Novosibirsk, Russian Federation
Novosibirsk State University, Novosibirsk, Russian Federation
Nazarbayev University, Nur-Sultan, Kazakhstan

Sobolev Institute of Mathematics
Novosibirsk State University
Nazarbayev University

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