Characterising SJT reducibility

TL;DR

This paper explores SJT reducibility, a weaker form of Turing reducibility, providing characterizations on K-trivial sets and extending lowness paradigms to weak reducibilities.

Contribution

It introduces and characterizes SJT reducibility on K-trivial sets, extending classical lowness paradigms to weak reducibility notions.

Findings

Characterizations of SJT reducibility on K-trivial sets

Extension of lowness paradigms to weak reducibilities

First analysis of SJT reducibility in this context

Abstract

SJT reducibility between sets $A,B \subseteq \mathbb N$ is defined by $A \le_{SJT} B$ if for each computable function $h$ that is unbounded and nondecreasing, there is an $h$-bounded uniformly $B$-c.e.\ trace $(T_n)_{n \in \mathbb N} $ such that for each $n$, the value $J^A(n)$ of the jump is in $T_n$, if defined. This reducibility is slightly weaker than Turing reducibility. We study SJT reducibility, and as a main result give several characterisations of it on the $K$-trivial sets. This is the first case of extending the three lowness paradigms, weak as an oracle, computed by many, and inert, to the setting of weak reducibilities.