We compare the degrees of enumerability and the closed Medvedev degrees and find that many situations occur. There are nonzero closed degrees that do not bound nonzero degrees of enumerability, there are nonzero degrees of enumerability that do not bound nonzero closed degrees, and there are degrees that are nontrivially both degrees of enumerability and closed degrees. We also show that the compact degrees of enumerability exactly correspond to the cototal enumeration degrees.

Shafer, P., Sorbi, A. (2019). Comparing the degrees of enumerability and the closed Medvedev degrees. ARCHIVE FOR MATHEMATICAL LOGIC, 58(5-6), 527-542 [10.1007/s00153-018-0648-x].

Comparing the degrees of enumerability and the closed Medvedev degrees

Sorbi, Andrea
2019-01-01

Abstract

We compare the degrees of enumerability and the closed Medvedev degrees and find that many situations occur. There are nonzero closed degrees that do not bound nonzero degrees of enumerability, there are nonzero degrees of enumerability that do not bound nonzero closed degrees, and there are degrees that are nontrivially both degrees of enumerability and closed degrees. We also show that the compact degrees of enumerability exactly correspond to the cototal enumeration degrees.
2019
Shafer, P., Sorbi, A. (2019). Comparing the degrees of enumerability and the closed Medvedev degrees. ARCHIVE FOR MATHEMATICAL LOGIC, 58(5-6), 527-542 [10.1007/s00153-018-0648-x].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11365/1063911