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This article is cited in 11 scientific papers (total in 11 papers)
Initial segments of computable linear orders with additional computable predicates
M. V. Zubkov N. G. Chebotarev Research Institute of Mathematics and Mechanics, Kazan State University, Kazan, Russia
Abstract:
We study computable linear orders with computable neighborhood and block predicates. In particular, it is proved that there exists a computable linear order with a computable neighborhood predicate, having a $\Pi^0_1$-initial segment which is isomorphic to no computable order with a computable neighborhood predicate. On the other hand, every $\Sigma^0_1$-initial segment of such an order has a computable copy enjoying a computable neighborhood predicate.
Similar results are stated for computable linear orders with a computable block predicate replacing a neighborhood relation. Moreover, using the results obtained, we give a simpler proof for the Coles–Downey–Khoussainov theorem on the existence of a computable linear order with $\Pi^0_2$-initial segment, not having a computable copy.
Keywords:
computability, recursiveness, linear order, initial segment.
Received: 24.01.2008 Revised: 20.03.2009
Citation:
M. V. Zubkov, “Initial segments of computable linear orders with additional computable predicates”, Algebra Logika, 48:5 (2009), 564–579; Algebra and Logic, 48:5 (2009), 321–329
Linking options:
https://www.mathnet.ru/eng/al414 https://www.mathnet.ru/eng/al/v48/i5/p564
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