English

A minimal set low for speed

Logic 2020-11-19 v1

Abstract

An oracle AA is low-for-speed if it is unable to speed up the computation of a set which is already computable: if a decidable language can be decided in time t(n)t(n) using AA as an oracle, then it can be decided without an oracle in time p(t(n))p(t(n)) for some polynomial pp. The existence of a set which is low-for-speed was first shown by Bayer and Slaman who constructed a non-computable computably enumerable set which is low-for-speed. In this paper we answer a question previously raised by Bienvenu and Downey, who asked whether there is a minimal degree which is low-for-speed. The standard method of constructing a set of minimal degree via forcing is incompatible with making the set low-for-speed; but we are able to use an interesting new combination of forcing and full approximation to construct a set which is both of minimal degree and low-for-speed.

Cite

@article{arxiv.2011.09174,
  title  = {A minimal set low for speed},
  author = {Rod Downey and Matthew Harrison-Trainor},
  journal= {arXiv preprint arXiv:2011.09174},
  year   = {2020}
}
R2 v1 2026-06-23T20:20:27.191Z