Abstract
Consider a Martin-Löf random \({\Delta^0_2}\) set Z. We give lower bounds for the number of changes of \(Z_s \upharpoonright n\) for computable approximations of Z. We show that each nonempty \({\Pi^0_1}\) class has a low member Z with a computable approximation that changes only o(2n) times. We prove that each superlow ML-random set already satisfies a stronger randomness notion called balanced randomness, which implies that for each computable approximation and each constant c, there are infinitely many n such that \(Z_s\upharpoonright n\) changes more than c 2n times.
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© 2010 Springer-Verlag Berlin Heidelberg
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Figueira, S., Hirschfeldt, D., Miller, J.S., Ng, K.M., Nies, A. (2010). Counting the Changes of Random \({\Delta^0_2}\) Sets. In: Ferreira, F., Löwe, B., Mayordomo, E., Mendes Gomes, L. (eds) Programs, Proofs, Processes. CiE 2010. Lecture Notes in Computer Science, vol 6158. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-13962-8_18
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DOI: https://doi.org/10.1007/978-3-642-13962-8_18
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-642-13961-1
Online ISBN: 978-3-642-13962-8
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