The complexity of finding top-toda-equivalence-class members

Abstract

We identify two properties that for P-selective sets are effectively computable. Namely we show that, for any P-selective set, finding a string that is in a given length's top Toda equivalence class (very informally put, a string from ∑n that the set's P-selector function declares to be most likely to belong to the set) is FP∑2p computable, and we show that each P-selective set contains a weakly-P∑2p-rankable subset. © Springer-Verlag 2004.