Article ID Journal Published Year Pages File Type
4662252 Annals of Pure and Applied Logic 2012 33 Pages PDF
Abstract

In applications of the fine hierarchies their characterizations in terms of the so called alternating trees are of principal importance. Also, in many cases a suitable version of many–one reducibility exists that fits a given fine hierarchy. With a use of Priestley duality we obtain a surprising result that suitable versions of alternating trees and of m-reducibilities may be found for any given fine hierarchy, i.e. the methods of alternating trees andm-reducibilities are quite general, which is of some methodological interest.Along with the hierarchies of sets, we consider also more general hierarchies ofk-partitions and in this context propose some new notions and establish new results, in particular extend the above-mentioned results for hierarchies of sets.

Related Topics
Physical Sciences and Engineering Mathematics Logic