English

On Splits of Computably enumerable sets

Logic 2016-08-09 v4

Abstract

Our focus will be on the computably enumerable (c.e.) sets and trivial, non-trivial, Friedberg, and non-Friedberg splits of the c.e. sets. Every non-computable set has a non-trivial Friedberg split. Moreover, this theorem is uniform. V. Yu. Shavrukov recently answered the question which c.e. sets have a non-trivial non-Friedberg splitting and we provide a different proof of his result. We end by showing there is no uniform splitting of all c.e. sets such that all non-computable sets are non-trivially split and, in addition, all sets with a non-trivial non-Friedberg split are split accordingly.

Cite

@article{arxiv.1605.03034,
  title  = {On Splits of Computably enumerable sets},
  author = {Peter Cholak},
  journal= {arXiv preprint arXiv:1605.03034},
  year   = {2016}
}

Comments

Submitted. This version corrects a number of issues raised by the referees. Our thanks to the referees. Learned about another related splitting theorem by Hammond which is now included

R2 v1 2026-06-22T13:57:33.058Z