Article ID Journal Published Year Pages File Type
8904268 Annals of Pure and Applied Logic 2018 21 Pages PDF
Abstract
Using a modification of the invariant Jensen forcing of [11], we define a model of ZFC, in which, for a given n≥3, there exists a lightface Πn1-set of reals, which is a E0-equivalence class, hence a countable set, and which does not contain any OD element, while every non-empty countable Σn1-set of reals is constructible, hence contains only OD reals.
Keywords
Related Topics
Physical Sciences and Engineering Mathematics Logic
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