Abstract
In this paper we study the question as to which computable algebras are isomorphic to non-computable \(\Pi_{1}^{0}\)-algebras. We show that many known algebras such as the standard model of arithmetic, term algebras, fields, vector spaces and torsion-free abelian groups have non-computable\(\Pi_{1}^{0}\)-presentations. On the other hand, many of this structures fail to have non-computable \(\Sigma_{1}^{0}\)-presentation.
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This research was partially supported by the Marsden Fund of New Zealand. The third author’s research was partially supported by RFFR grant No. 02-01-00593 and Council for Grants under RF President, project NSh-2112.2003.1.
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Khoussainov, B., Slaman, T. & Semukhin, P. \(\Pi^0_1\)-Presentations of Algebras. Arch. Math. Logic 45, 769–781 (2006). https://doi.org/10.1007/s00153-006-0013-3
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DOI: https://doi.org/10.1007/s00153-006-0013-3