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Extending Cooper’s theorem to Δ30 Turing degrees

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dc.date.accessioned 2019-01-22T20:57:41Z
dc.date.available 2019-01-22T20:57:41Z
dc.date.issued 2018
dc.identifier.issn 2211-3568
dc.identifier.uri https://dspace.kpfu.ru/xmlui/handle/net/149630
dc.description.abstract © 2018 - IOS Press and the authors. All rights reserved. In 1971 B. Cooper proved that there exists a 2-c.e. Turing degree which doesn't contain a c.e. set. Thus, he showed that the second level of the Ershov hierarchy is proper. In this paper we investigate proper levels of some extensions of the Ershov hierarchy to higher levels of the arithmetical hierarchy. Thus we contribute to the theory of ' " 3 0 -degrees by extending Cooper's theorem to some levels of the fine hierarchy within ' " 3 0 -sets.
dc.relation.ispartofseries Computability
dc.subject arithmetical hierarchy
dc.subject Ershov's hierarchy
dc.subject fine hierarchy
dc.subject Turing degrees
dc.subject £ 2 0 -sets
dc.title Extending Cooper’s theorem to Δ30 Turing degrees
dc.type Article
dc.relation.ispartofseries-issue 2-3
dc.relation.ispartofseries-volume 7
dc.collection Публикации сотрудников КФУ
dc.relation.startpage 289
dc.source.id SCOPUS22113568-2018-7-23-SID85048717364

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  • Публикации сотрудников КФУ Scopus [24551]
    Коллекция содержит публикации сотрудников Казанского федерального (до 2010 года Казанского государственного) университета, проиндексированные в БД Scopus, начиная с 1970г.

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