Asymptotic density and computability
Izvestiâ vysših učebnyh zavedenij. Matematika, no. 10 (2021), pp. 3-14
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We show that a set is bi-immune if and only if there are no computable permutations that arrange the set into a generically computable set or an effectively densely computable set. An example of a coarsely computable bi-immune set is constructed. It is also proved that for any set there is a permutation from the same Turing degree that arranges the set into an effectively densely computable set. The upper densities of some sets are studied.
Keywords:
asymptotic density, generic complexity, Turing degree.
Mots-clés : bi-immune set
Mots-clés : bi-immune set
@article{IVM_2021_10_a0,
author = {I. I. Batyrshin},
title = {Asymptotic density and computability},
journal = {Izvesti\^a vys\v{s}ih u\v{c}ebnyh zavedenij. Matematika},
pages = {3--14},
publisher = {mathdoc},
number = {10},
year = {2021},
language = {ru},
url = {http://geodesic.mathdoc.fr/item/IVM_2021_10_a0/}
}
I. I. Batyrshin. Asymptotic density and computability. Izvestiâ vysših učebnyh zavedenij. Matematika, no. 10 (2021), pp. 3-14. http://geodesic.mathdoc.fr/item/IVM_2021_10_a0/