Reductions between types of numberings

  • Ian Herbert
  • , Sanjay Jain
  • , Steffen Lempp
  • , Manat Mustafa
  • , Frank Stephan

Research output: Contribution to journalArticlepeer-review

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 to use these reductions to simplify some constructions of specific semilattices. 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 languageEnglish
Article number102716
Pages (from-to)1-30
Number of pages30
JournalAnnals of Pure and Applied Logic
Volume170
Issue number12
DOIs
Publication statusPublished - Dec 2019

Keywords

  • Ordinals in recursion theory
  • Recursively enumerable sets
  • Reducibilities between numberings
  • Theory of numberings in the difference hierarchy
  • n-r.e. sets

ASJC Scopus subject areas

  • Logic

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