Index sets of decidably categorical models with unary functional symbols

Index sets of decidably categorical models with unary functional symbols Full article

Journal

Algebra and Logic
ISSN: 0002-5232 , E-ISSN: 1573-8302

Output data

Year: 2026, Volume: 65, Number: 1, Pages: 10-20 Pages count : 11 DOI: 10.1007/s10469-026-09850-4

Tags

computable model, strongly constructivizable model, decidable model, computable categoricity, decidable categoricity, index set, injective unar

Authors

Bazhenov N.A. ^1,2 , Marchuk M.I. ^1,2

Affiliations

1	Sobolev Institute of Mathematics, Siberian Branch of the Russian Academy of Sciences
2	Novosibirsk State University, Novosibirsk, Russia

Funding (1)

Министерство науки и высшего образования РФ

FWNF-2026-0032

We obtain a criterion for decidable categoricity of injective unars. Exact complexity estimates are established for the index sets of the classes of strongly constructivizable injective unars and decidably categorical injective unars. It is shown that the index set of decidably categorical structures in a signature consisting of two unary functional symbols is Σ^0_(ω+2)-complete.

Bazhenov N.A. , Marchuk M.I.
Index sets of decidably categorical models with unary functional symbols
Algebra and Logic. 2026. V.65. N1. P.10-20. DOI: 10.1007/s10469-026-09850-4

Submitted:	Jul 12, 2026
Accepted:	Sep 2, 2026
Published online:	Oct 15, 2026

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