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arXiv · 2602.23572

Characterising SJT reducibility

Noam Greenberg·Andre Nies·Dan Turetsky
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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.

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BibTeXRIS

Noam Greenberg, Andre Nies, Dan Turetsky. 2026-02-27. Characterising SJT reducibility. https://doi.org/10.1017/jsl.2026.10228

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