Cuppings and cappings in enumeration \(\Delta_2^0\) degrees. (English. Russian original) Zbl 0966.03042
Algebra Logika 39, No. 5, 547-566 (2000); translation in Algebra Logic 39, No. 5, 313-323 (2000).
The author proves that there is an incomplete \(\Pi_1^0\)-\(e\)-degree that has no capping property relative to \(\Delta_2^0\)-\(e\)-degrees, and that each low \(e\)-degree possesses the capping property in \(\Delta_2^0\)-\(e\)-degrees.
Reviewer: A.S.Morozov (Novosibirsk)
MSC:
| 03D25 | Recursively (computably) enumerable sets and degrees |
| 03D30 | Other degrees and reducibilities in computability and recursion theory |
