Please use this identifier to cite or link to this item: https://hdl.handle.net/10356/154823
Title: Cupping and jump classes in the computably enumerable degrees
Authors: Greenberg, Noam
Ng, Keng Meng
Wu, Guohua
Keywords: Science::Mathematics
Issue Date: 2020
Source: Greenberg, N., Ng, K. M. & Wu, G. (2020). Cupping and jump classes in the computably enumerable degrees. Journal of Symbolic Logic, 85(4), 1499-1545. https://dx.doi.org/10.1017/jsl.2020.36
Project: MOE2016-T2-1-083 (M4020333)
RG32/16 (M4011672)
RG111/19 (M4012245)
MOE2015-T2-2-055
Journal: Journal of Symbolic Logic
Abstract: We show that there is a cuppable c.e. degree, all of whose cupping partners are high. In particular, not all cuppable degrees are -cuppable, or indeed cuppable for any n, refuting a conjecture by Li. On the other hand, we show that one cannot improve highness to superhighness. We also show that the -cuppable degrees coincide with the array computable-cuppable degrees, giving a full understanding of the latter class.
URI: https://hdl.handle.net/10356/154823
ISSN: 0022-4812
DOI: 10.1017/jsl.2020.36
Rights: © 2020 Association for Symbolic Logic. All rights reserved.
Fulltext Permission: none
Fulltext Availability: No Fulltext
Appears in Collections:SPMS Journal Articles

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