Article ID Journal Published Year Pages File Type
6424850 Annals of Pure and Applied Logic 2011 40 Pages PDF
Abstract

• We define a notion of order of indiscernibility type of a structure by analogy with Mitchell order on measures; we use this to define a hierarchy of strong axioms of infinity defined through normal filters, the α-weakly Erdős hierarchy. The filters in this hierarchy can be seen to be generated by sets of ordinals where these indiscernibility orders on structures dominate the canonical functions.• The limit axiom of this is that of greatly Erdős and we use it to calibrate some strengthenings of the Chang property, one of which, CC+, is equiconsistent with a Ramsey cardinal, and implies that ω3=(ω2+)K where K is the core model built with non-overlapping extenders - if it is rigid, and others which are a little weaker. As one corollary we have: TheoremIf CC+∧¬□ω2then there is an inner model with a strong cardinal. • We define an α-Jónsson hierarchy to parallel the α-Ramsey hierarchy, and show that κ being α-Jónsson implies that it is α-Ramsey in the core model.

Related Topics
Physical Sciences and Engineering Mathematics Logic
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