Abstract
We study the relationship between randomness and effective bi-immunity. Greenberg and Miller have shown that for any oracle X, there are arbitrarily slow-growing \(\mathrm {DNR}\) functions relative to X that compute no Martin-Löf random set. We show that the same holds when Martin-Löf randomness is replaced with effective bi-immunity. It follows that there are sequences of effective Hausdorff dimension 1 that compute no effectively bi-immune set.
We also establish an important difference between the two properties. The class Low(MLR, EBI) of oracles relative to which every Martin-Löf random is effectively bi-immune contains the jump-traceable sets, and is therefore of cardinality continuum.
This work was partially supported by a grant from the Simons Foundation (#315188 to Bjørn Kjos-Hanssen). This material is based upon work supported by the National Science Foundation under Grant No. 1545707.
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- 1.
A simple set is an r.e. set whose complement is immune.
- 2.
We use the recursion theorem here.
References
Ambos-Spies, K., Kjos-Hanssen, B., Lempp, S., Slaman, T.A.: Comparing DNR and WWKL. J. Symbolic Logic 69(4), 1089–1104 (2004)
Barmpalias, G., Lewis, A.E.M., Ng, K.M.: The importance of \(\Pi ^0_1\) classes in effective randomness. J. Symbolic Logic 75(1), 387–400 (2010)
Beros, A.A.: A DNC function that computes no effectively bi-immune set. Arch. Math. Logic 54(5–6), 521–530 (2015)
Greenberg, N., Miller, J.S.: Lowness for Kurtz randomness. J. Symbolic Logic 74(2), 665–678 (2009)
Greenberg, N., Miller, J.S.: Diagonally non-recursive functions and effective Hausdorff dimension. Bull. Lond. Math. Soc. 43(4), 636–654 (2011)
Jockusch Jr., C.G.: Degrees of functions with no fixed points. In: Logic, methodology and philosophy of science, VIII (Moscow, 1987), vol. 126. Studies in Logic and the Foundations of Mathematics, pp. 191–201, North-Holland, Amsterdam (1989)
Jockusch Jr., C.G., Lewis, A.E.M.: Diagonally non-computable functions and bi-immunity. J. Symbolic Logic 78(3), 977–988 (2013)
Kechris, A.S.: Classical Descriptive Set Theory. Graduate Texts in Mathematics, vol. 156. Springer, New York (1995)
Khan, M., Miller, J.S.: Forcing with bushy trees. http://www.math.hawaii.edu/khan/bushy_trees.pdf
Kjos-Hanssen, B., Merkle, W., Stephan, F.: Kolmogorov complexity and the recursion theorem. Trans. Amer. Math. Soc. 363(10), 5465–5480 (2011)
Martin, D.A.: Completeness, the recursion theorem, and effectively simple sets. Proc. Am. Math. Soc. 17(4), 838–842 (1966)
Nies, A., Stephan, F., Terwijn, S.A.: Randomness, relativization and Turing degrees. J. Symbolic Logic 70(2), 515–535 (2005)
Post, E.L.: Recursively enumerable sets of positive integers and their decision problems. Bull. Amer. Math. Soc. 50, 284–316 (1944)
Sacks, G.E.: A simple set which is not effectively simple. Proc. Am. Math. Soc. 15(1), 51–55 (1964)
Smullyan, R.M.: Effectively simple sets. Proc. Am. Math. Soc. 15(6), 893–895 (1964)
Stephan, F.: Martin-Löf random and PA-complete sets. In: Logic Colloquium 2002, vol. 27. Lecture Notes in Logic, pp. 342–348. Association for Symbolic Logic, La Jolla, CA (2006)
Acknowledgements
The authors would like to thank Uri Andrews, Daniel Turetsky, Linda Westrick, Rohit Nagpal, and Ashutosh Kumar for helpful discussions.
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Beros, A.A., Khan, M., Kjos-Hanssen, B. (2017). Effective Bi-immunity and Randomness. In: Day, A., Fellows, M., Greenberg, N., Khoussainov, B., Melnikov, A., Rosamond, F. (eds) Computability and Complexity. Lecture Notes in Computer Science(), vol 10010. Springer, Cham. https://doi.org/10.1007/978-3-319-50062-1_38
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