JUMP OPERATOR AND YATES DEGREES.

In [9], Yates proved the existence of a Turing degree a such that 0, 0′ are the only c.e. degrees comparable with it. By Slaman and Steel [7], every degree below 0′ has a 1-generic complement, and as a consequence, Yates degrees can be 1-generic, and hence can be low. In this paper, we prove that Yates degrees occur in every jump class. [ABSTRACT FROM AUTHOR]