Abstract:
We consider the question of randomness of the probability ΩU[X] that an optimal Turing machine U halts and outputs a string in a fixed set X. The main results are as follows: ΩU[X] is random whenever X is Σn0-complete or Πn0-complete for some n ≥ 2. However, for n ≥ 2, ΩU[X] is not n-random when X is Σn0 or Πn0. Nevertheless, there exists Δn+10 sets such that ΩU[X] is n-random. There are Δ20 sets X such that ΩU[X] is rational. Also, for every n ≥ 1, there exists a set X which is Δn+10 and Σn 0-hard such that ΩU[X] is not random. We also look at the range of ΩU as an operator. We prove that the set {ΩU[X]: X ⊆ 2<ω} is a finite union of closed intervals. It follows that for any optimal machine U and any sufficiently small real r, there is a set X ⊆ 2<ω recursive in ∅′ ⊕ r, such that ΩU[X] = r. The same questions are also considered in the context of infinite computations, and lead to similar results. © 2006, Association for Symbolic Logic.
Registro:
Documento: |
Artículo
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Título: | Randomness and halting probabilities |
Autor: | Becher, V.; Figueira, S.; Grigorieff, S.; Miller, J.S. |
Filiación: | Departamento de Computación, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina CONICET, Argentina LIAFA, Université Paris 7, CNRS, France Department of Mathematics, University of Connecticut, United States
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Año: | 2006
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Volumen: | 71
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Número: | 4
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Página de inicio: | 1411
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Página de fin: | 1430
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DOI: |
http://dx.doi.org/10.2178/jsl/1164060463 |
Título revista: | Journal of Symbolic Logic
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Título revista abreviado: | J. Symb. Logic
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ISSN: | 00224812
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Registro: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00224812_v71_n4_p1411_Becher |
Referencias:
- Becher, V., Grigorieff, S., (2005) Random Reals and Possibly Infinite Computations. Part I: Randomness in ∅′, 70 (3), pp. 891-913. , this JOURNAL
- Random Reals and Possibly Infinite Computations. Part II: From Index Sets to Higher Order Randomness, , In preparation
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- Odifreddi, P., (1990) Classical Recursion Theory, , North-Holland
- Rogers Jr., H., (1968) Theory of Recursive Functions and Effective Computability, , McGraw Hill, New York
- Solovay, R.M., (1974) Draft of Paper (Or Series of Papers) on Chaitin's Work, Done for the Most Part during the Period of Sept.-Dec., , unpublished manuscript, IBM Thomas Watson Research Center, Yorktown Heights, NY, 215 pages
Citas:
---------- APA ----------
Becher, V., Figueira, S., Grigorieff, S. & Miller, J.S.
(2006)
. Randomness and halting probabilities. Journal of Symbolic Logic, 71(4), 1411-1430.
http://dx.doi.org/10.2178/jsl/1164060463---------- CHICAGO ----------
Becher, V., Figueira, S., Grigorieff, S., Miller, J.S.
"Randomness and halting probabilities"
. Journal of Symbolic Logic 71, no. 4
(2006) : 1411-1430.
http://dx.doi.org/10.2178/jsl/1164060463---------- MLA ----------
Becher, V., Figueira, S., Grigorieff, S., Miller, J.S.
"Randomness and halting probabilities"
. Journal of Symbolic Logic, vol. 71, no. 4, 2006, pp. 1411-1430.
http://dx.doi.org/10.2178/jsl/1164060463---------- VANCOUVER ----------
Becher, V., Figueira, S., Grigorieff, S., Miller, J.S. Randomness and halting probabilities. J. Symb. Logic. 2006;71(4):1411-1430.
http://dx.doi.org/10.2178/jsl/1164060463