dc.contributor.author |
Arslanov M. |
|
dc.date.accessioned |
2018-09-18T20:17:12Z |
|
dc.date.available |
2018-09-18T20:17:12Z |
|
dc.date.issued |
2014 |
|
dc.identifier.issn |
1066-369X |
|
dc.identifier.uri |
https://dspace.kpfu.ru/xmlui/handle/net/138312 |
|
dc.description.abstract |
In this paper we investigate questions about the definability of classes of n-computably enumerable (c. e.) sets and degrees in the Ershov difference hierarchy. It is proved that the class of all c. e. sets is definable under the set inclusion ⊆ in all finite levels of the difference hierarchy. It is also proved the definability of all m-c. e. degrees in each higher level of the hierarchy. Besides, for each level n, n ≥ 2, of the hierarchy a definable non-trivial subset of n-c. e. degrees is established. © 2014 Allerton Press, Inc. |
|
dc.relation.ispartofseries |
Russian Mathematics |
|
dc.subject |
and phrases: computably enumerable sets |
|
dc.subject |
definable relations |
|
dc.subject |
high degrees |
|
dc.subject |
major subsets |
|
dc.subject |
Turing degrees of unsolvability |
|
dc.title |
Definable relations in Turing degree structures |
|
dc.type |
Article |
|
dc.relation.ispartofseries-issue |
2 |
|
dc.relation.ispartofseries-volume |
58 |
|
dc.collection |
Публикации сотрудников КФУ |
|
dc.relation.startpage |
64 |
|
dc.source.id |
SCOPUS1066369X-2014-58-2-SID84897775555 |
|