Degrees containing members of thin II1 classes are dense and co-dense

• Main Authors: Downey, Rodney G., Wu, Guohua, Yang, Yue
• Other Authors: School of Physical and Mathematical Sciences
• Format: Article
• Language: English
• Published: 2020
• Subjects: Science::Mathematics; Π10 Classes; Turing Degrees
• Online Access: https://hdl.handle.net/10356/142298
• Institution: Nanyang Technological University

In [Countable thin II1 classes, Ann. Pure Appl. Logic 59 (1993) 79-139], Cenzer, Downey, Jockusch and Shore proved the density of degrees (not necessarily c.e.) containing members of countable thin II1 classes. In the same paper, Cenzer et al. also proved the existence of degrees containing no membe...