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arXiv · 2603.08006

Primitive recursive categoricity spectra

Nikolay Bazhenov·Heer Tern Koh·Keng Meng Ng
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Abstract

We study the primitive recursive analogue of computable categoricity spectra for various natural classes of structures. We show that these notions coincide for all relatively $\Delta_{2}^{0}$-categorical equivalence structures and linear orders, relatively $\Delta_{3}^{0}$-categorical Boolean algebras, and computably categorical tree as partial orders.

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Nikolay Bazhenov, Heer Tern Koh, Keng Meng Ng. 2026-03-09. Primitive recursive categoricity spectra. https://arxiv.org/abs/2603.08006

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