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|Title:||Nonhemimaximal degrees and the high/low hierarchy||Authors:||Fang, Chengling
|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
|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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