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https://hdl.handle.net/10356/99244
Title: | Nonhemimaximal degrees and the high/low hierarchy | Authors: | Fang, Chengling Wu, Guohua |
Keywords: | DRNTU::Science::Mathematics::Mathematical logic | Issue Date: | 2012 | Source: | Fang, C., & Wu, G. (2012). Nonhemimaximal degrees and the high/low hierarchy. Journal of symbolic logic, 77(2), 433-446. | Series/Report no.: | Journal of symbolic logic | Abstract: | After showing the downwards density of nonhemimaximal degrees, Downey and Stob continued to prove that the existence of a low₂, but not low, nonhemimaximal degree, and their proof uses the fact that incomplete m-topped degrees are low₂ but not low. As commented in their paper, the construction of such a nonhemimaximal degree is actually a primitive 0''' argument. In this paper, we give another construction of such degrees, which is a standard 0''-argument, much simpler than Downey and Stob's construction mentioned above. | URI: | https://hdl.handle.net/10356/99244 http://hdl.handle.net/10220/17146 |
ISSN: | 0022-4812 | DOI: | 10.2178/jsl/1333566631 | Fulltext Permission: | none | Fulltext Availability: | No Fulltext |
Appears in Collections: | SPMS Journal Articles |
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