Published online by Cambridge University Press: 12 March 2014
In recent years higher recursion theory has experienced a deep interaction with other areas of logic, particularly set theory (fine structure, forcing, and combinatorics) and infinitary model theory. In this paper we wish to illustrate this interaction by surveying the progress that has been made in two areas: the global theory of the κ-degrees and the study of closure ordinals.
This paper accompanies an invited lecture given by the author at the Spring 1981 Meeting of the ASL in Milwaukee, Wisconsin. The preparation of this paper was supported by NSF Grant # MCS 7906084.