Recursion Theory Week [electronic resource] : Proceedings of a Conference held in Oberwolfach, FRG, March 19–25, 1989 / edited by Klaus Ambos-Spies, Gert H. Müller, Gerald E. Sacks.

Honest polynomial reductions and exptally sets -- On the structure of degrees below O? -- Positive solutions to Post's problem -- The metamathematics of Fraïssé's order type conjecture -- Enumeration reducibility, nondeterministic computations and relative computability of partial functions -- Notes on the O? priority method with special attention to density results -- Array nonrecursive sets and multiple permitting arguments -- Superbranching degrees -- A direct construction of a minimal recursively enumerable truth-table degree -- ?2-induction and the construction of a high degree -- Undecidability and initial segments of the wtt-degrees ?0? -- Randomness and generalizations of fixed point free functions -- Recursive enumeration without repetition revisited -- Priority arguments using iterated trees of strategies -- On the relationship between the complexity, the degree, and the extension of a computable set -- Polynomially isolated sets -- A characterization of effective topological spaces.

These proceedings contain research and survey papers from many subfields of recursion theory, with emphasis on degree theory, in particular the development of frameworks for current techniques in this field. Other topics covered include computational complexity theory, generalized recursion theory, proof theoretic questions in recursion theory, and recursive mathematics.