English

Highness properties close to PA-completeness

Logic 2019-12-09 v1

Abstract

Suppose we are given a computably enumerable object arise from algorithmic randomness or computable analysis. We are interested in the strength of oracles which can compute an object that approximates this c.e. object. It turns out that, depending on the type of object, the resulting highness property is either close to, or equivalent to being PA-complete. We examine, for example, dominating a c.e. martingale by an oracle-computable martingale, computing compressions functions for two variants of Kolmogorov complexity, and computing subtrees of positive measure of a given Π10\Pi^0_1 tree of positive measure without dead ends. We prove a separation result from PA-completeness for the latter property, called the \emph{continuous covering property}. We also separate the corresponding principles in reverse mathematics.

Keywords

Cite

@article{arxiv.1912.03016,
  title  = {Highness properties close to PA-completeness},
  author = {Noam Greenberg and Joseph S. Miller and Andre Nies},
  journal= {arXiv preprint arXiv:1912.03016},
  year   = {2019}
}
R2 v1 2026-06-23T12:37:48.941Z