Abstract
This paper considers reductions between types of numberings; these reductions
preserve the Rogers Semilattice of the numberings reduced and also preserve
the number of minimal and positive degrees in their semilattice. It is shown how these reductions can be used to answer some open problems. Furthermore, it is shown that for the basic types of numberings, one can reduce the left-r.e. numberings to the r.e. numberings and the k-r.e. numberings to the (k + 1)-r.e. numberings; all further reductions are obtained by concatenating these reductions.
preserve the Rogers Semilattice of the numberings reduced and also preserve
the number of minimal and positive degrees in their semilattice. It is shown how these reductions can be used to answer some open problems. Furthermore, it is shown that for the basic types of numberings, one can reduce the left-r.e. numberings to the r.e. numberings and the k-r.e. numberings to the (k + 1)-r.e. numberings; all further reductions are obtained by concatenating these reductions.
Original language | English |
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Pages (from-to) | 1-30 |
Number of pages | 30 |
Journal | Annals of Pure and Applied Logic |
DOIs | |
Publication status | Published - Jul 4 2019 |