Extending Cooper’s theorem to Δ30 Turing degrees

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.