Abstract
The current work includes a result announced in the year 2012 which was unproven until now. The result shows that there is a co-r.e. tree with uncountably many infinite branches such that the nonisolated infinite branches of the constructed tree are all nonrecursive, generalised low, hyperimmune-free and form a perfect tree.
Frank Stephan and Yang Yue have been supported in part by the Singapore Ministry of Education Tier 2 grant AcRF MOE2019-T2-2-121/R146-000-304-112 as well as by the NUS Tier 1 grants AcRF R146-000-337-114 and R252-000-C17-114. Keng Meng Ng is supported by the Singapore Ministry of Education grant RG23/19 at NTU. Liang Yu was supported by NSFC grant No. 12025103.
This is a preview of subscription content, log in via an institution.
Buying options
Tax calculation will be finalised at checkout
Purchases are for personal use only
Learn about institutional subscriptionsReferences
Calude, C.S.: Information and Randomness - An Algorithmic Perspective, 2nd edn. Springer, Heidelberg (2002). https://doi.org/10.1007/978-3-662-04978-5
Dekker, J.C.: A theorem on hypersimple sets. Proc. Am. Math. Soc. 5, 791–796 (1954)
Downey, R.G.: On \(\Pi ^0_1\)-classes and their ranked points. Notre Dame J. Formal Logic 32(4), 499–512 (1991)
Franklin, J., Stephan, F.: Schnorr-trivial sets and truth-table reducibility. J. Symb. Logic 75(2), 501–521 (2010)
Friedberg, R.: A criterion for completeness of degrees of unsolvability. J. Symb. Logic 22, 159–160 (1957)
Hölzl, R., Porter, C.P.: Randomness for computable measures and initial segment complexity. Ann. Pure Appl. Logic 168(4), 860–886 (2017)
Hirschfeldt, D.R., Jockusch Jr, C.G., Schupp, P.E.: Coarse computability, the density metric, Hausdorff distances between Turing degrees, perfect trees, and reverse mathematics. Technical report on http://arxiv.org/abs/2106.13118 (2021)
Jockusch, C.G., Soare, R.I.: \(\Pi ^0_1\) classes and degrees of theories. Trans. Am. Math. Soc. 173, 33–56 (1972). https://doi.org/10.1007/s00153-012-0310-y
Li, M., Vitányi, P.: An Introduction to Kolmogorov Complexity and its Applications. Springer, New York (2019). https://doi.org/10.1007/978-0-387-49820-1
Matiyasevich, Y.V.: Diofantovost’ perechislimykh mnozhestv. Doklady Akademii Nauk SSSR, 191, 297-282 (1970). (in Russian). English translation: Enumerable sets are Diophantine. Soviet Math. Doklady 11, 354-358 (1970)
Miller, W., Martin, D.: The degrees of hyperimmune sets. Z. für Math. Logik und Grundl. der Math. 14, 159–166 (1968)
Ng, K.M., Stephan, F., Yang, Y., Yu, L.: The computational aspects of hyperimmunefree degrees. In: Proceedings of the Twelfth Asian Logic Conference, pp. 271–284. World Scientific (2013)
Ng, K.M., Yu, H.: Effective domination and the bounded jump. Notre Dame J. Formal Logic 61(2), 203–225 (2020)
Nies, A.: Reals which compute little. In: Proceedings of Logic Colloquium 2002, Lecture Notes in Logic, vol. 27, pp. 261–275 (2002)
Nies, A.: Computability and Randomness. Oxford University Press, Oxford (2009)
Odifreddi, P.: Classical Recursion Theory. North-Holland, Amsterdam (1989)
Sacks, G.E.: On the degrees less than \({ 0}^{\prime }\). Ann. Math. 77, 211–231 (1963)
Soare, R.: Recursively Enumerable Sets and Degrees: A Study of Computable Functions and Computably Generated Sets. Springer, Heidelberg (1987)
Spector, C.: On degrees of unsolvability. Ann. Math. 64, 581–592 (1956)
Post, E.L.: Recursively enumerable sets of positive integers and their decision problems. Bull. Am. Math. Soc. 50, 284–316 (1944)
Triplett, M.A.: Algorithmic Complexity and Triviality. Bachelor Thesis, The University of Auckland, New Zealand (2014)
Yu, H.: On equivalence relations and bounded Turing degrees. Ph.D. dissertation. Nanyang Technological University, Singapore (2018)
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2022 The Author(s), under exclusive license to Springer Nature Switzerland AG
About this paper
Cite this paper
Ng, K.M., Stephan, F., Yang, Y., Yu, L. (2022). On Trees Without Hyperimmune Branches. In: Berger, U., Franklin, J.N.Y., Manea, F., Pauly, A. (eds) Revolutions and Revelations in Computability. CiE 2022. Lecture Notes in Computer Science, vol 13359. Springer, Cham. https://doi.org/10.1007/978-3-031-08740-0_20
Download citation
DOI: https://doi.org/10.1007/978-3-031-08740-0_20
Published:
Publisher Name: Springer, Cham
Print ISBN: 978-3-031-08739-4
Online ISBN: 978-3-031-08740-0
eBook Packages: Computer ScienceComputer Science (R0)