Nonhemimaximal degrees and the high/low hierarchy

• Main Authors: Fang, Chengling, Wu, Guohua
• Other Authors: School of Physical and Mathematical Sciences
• Format: Article
• Language: English
• Published: 2013
• Subjects: DRNTU::Science::Mathematics::Mathematical logic
• Online Access: https://hdl.handle.net/10356/99244; http://hdl.handle.net/10220/17146
• Institution: Nanyang Technological University

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 su...