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Algebra i logika, 2023, Volume 62, Number 4, Pages 441–457 DOI: https://doi.org/10.33048/alglog.2023.62.401
(Mi al2771)
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Decidable categoricity spectra for almost prime models
N. A. Bazhenovab, M. I. Marchukba a Sobolev Institute of Mathematics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk
b Novosibirsk State University
DOI:
https://doi.org/10.33048/alglog.2023.62.401
Abstract:
We study decidable categoricity spectra for almost prime models. For any computable collection $\{D_i\}_{i\in\omega}$, where $D_i$ either is a c.e. set or $D_i=PA$, we construct a sequence of almost prime models $\{\mathcal{M}_i\}_{i\in\omega}$ elementarily embedded in each other, in which case for any $i$ there exists a finite collection of constants such that the model $\mathcal{M}_i$ in the expansion by these constants has degree of decidable categoricity $\deg_T(D_i)$, if $D_i$ is a c.e. set, and has no degree of decidable categoricity if $D_i=PA$. The result obtained extends that of S. S. Goncharov, V. Harizanov, and R. Miller [Sib. Adv. Math., 30, No. 3, 200–212 (2020)].
Keywords:
computable model, decidable model, computable categoricity, decidable categoricity, autostability relative to strong constructivizations, degree of decidable categoricity, decidable categoricity spectrum, $PA$-degree.
Received: 28.10.2022 Revised: 19.07.2024
Citation:
N. A. Bazhenov, M. I. Marchuk, “Decidable categoricity spectra for almost prime models”, Algebra Logika, 62:4 (2023), 441–457; Algebra and Logic, 62:4 (2023), 291–302
Linking options:
https://www.mathnet.ru/eng/al2771 https://www.mathnet.ru/eng/al/v62/i4/p441
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