A local approach towards uniform Martin’s conjecture

Abstract: In 1967 Sacks asked whether there is degree invariant r.e. operator that maps x to a solution to Post's problem relativized for x. In 1975, Lachlan proved that the answer is no if we require the operator to be degree invariant in a uniform way. Sack's question can be considered the forefather of Martin's conjecture, a foundamental open problem that hypothizes that degree invariant functions under AD have limited possibilities of behavior. Following Lachlan's example, in the late 80s Slaman and Steel proved Martin's conjecture for unifromly degree invariant functions. We will show that half of this result is actually the consequence of phenomena that unifromly degree invariant functions already manisfest on single Turing degrees. We also present a joint result with Patrick Lutz, in which we show that Lachlan's result arises locally, too.

logic

Audience: researchers in the topic

Computability theory and applications

Series comments: Description: Computability theory, logic

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