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The $\Delta^0_\alpha$-computable enumerations of the classes of projective planes
A. K. Voĭtov Novosibirsk State University, Novosibirsk, Russia
Abstract:
Studying computable representations of projective planes, for the classes $K$ of pappian, desarguesian, and all projective planes, we prove that $K^c/_\simeq$ admits no hyperarithmetical Friedberg enumeration and admits a Friedberg $\Delta^0_{\alpha+3}$-computable enumeration up to a $\Delta^0_\alpha$-computable isomorphism.
Keywords:
pappian projective plane, desarguesian projective plane, freely generated projective plane, computable model, computable class of models, computable isomorphism.
Received: 19.01.2017
Citation:
A. K. Voǐtov, “The $\Delta^0_\alpha$-computable enumerations of the classes of projective planes”, Sibirsk. Mat. Zh., 59:2 (2018), 321–336; Siberian Math. J., 59:2 (2018), 252–263
Linking options:
https://www.mathnet.ru/eng/smj2974 https://www.mathnet.ru/eng/smj/v59/i2/p321
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