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JOURNALS // Algebra i logika // Archive

Algebra Logika, 2013 Volume 52, Number 5, Pages 535–552 (Mi al601)

This article is cited in 3 papers

Computable numberings of the class of Boolean algebras with distinguished endomorphisms

N. A. Bazhenovab

a Sobolev Institute of Mathematics, Siberian Branch, Russian Academy of Sciences, pr. Akad. Koptyuga 4, Novosibirsk, 630090, Russia
b Novosibirsk State University, ul. Pirogova 2, Novosibirsk, 630090, Russia

Abstract: We deal with computable Boolean algebras having a fixed finite number $\lambda$ of distinguished endomorphisms (briefly, $E_\lambda$-algebras). It is shown that the index set of $E_\lambda$-algebras is $\Pi^0_\2$-complete. It is proved that the class of all computable $E_\lambda$-algebras has a $\Delta^0_3$-computable numbering but does not have a $\Delta^0_2$-computable numbering, up to computable isomorphism. Also for the class of all computable $E_\lambda$-algebras, we explore whether there exist hyperarithmetical Friedberg numberings, up to $\Delta^0_\alpha$-computable isomorphism.

Keywords: computable Boolean algebra with distinguished endomorphisms, computable numbering, Friedberg numbering, index set, isomorphism problem.

UDC: 512.563+510.5+510.6

Received: 17.07.2013


 English version:
Algebra and Logic, 2013, 52:5, 355–366

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