An order-reversing embedding of Turing degrees into Arthur-Nimue-Merlin degrees

Fuente: arXiv
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Main Authors: Samra, Jean Abou, Madore, David Alexander
Format: Preprint
Published: 2026
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author Samra, Jean Abou
Madore, David Alexander
author_facet Samra, Jean Abou
Madore, David Alexander
contents The Arthur-Nimue-Merlin degrees are a generalization of the Turing degrees introduced by Kihara as a tangible description of the partially ordered set of Lawvere-Tierney topologies on the effective topos (equivalently, subtoposes of the effective topos). They are defined in terms of a three-player game that introduces both angelic and demonic non-determinism into oracle queries. We construct an order embedding of the Turing degrees with their order reversed into the Arthur-Nimue-Merlin degrees, whose image we call the "co-Turing degrees"; we then study the order relationship of these co-Turing degrees with the (naturally embedded) Turing degrees within the Arthur-Nimue-Merlin degrees.
format Preprint
id arxiv_https___arxiv_org_abs_2603_19946
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle An order-reversing embedding of Turing degrees into Arthur-Nimue-Merlin degrees
Samra, Jean Abou
Madore, David Alexander
Logic
Logic in Computer Science
03D30, 03G30, 03F65
The Arthur-Nimue-Merlin degrees are a generalization of the Turing degrees introduced by Kihara as a tangible description of the partially ordered set of Lawvere-Tierney topologies on the effective topos (equivalently, subtoposes of the effective topos). They are defined in terms of a three-player game that introduces both angelic and demonic non-determinism into oracle queries. We construct an order embedding of the Turing degrees with their order reversed into the Arthur-Nimue-Merlin degrees, whose image we call the "co-Turing degrees"; we then study the order relationship of these co-Turing degrees with the (naturally embedded) Turing degrees within the Arthur-Nimue-Merlin degrees.
title An order-reversing embedding of Turing degrees into Arthur-Nimue-Merlin degrees
topic Logic
Logic in Computer Science
03D30, 03G30, 03F65
url https://arxiv.org/abs/2603.19946