arXiv Analytics

Sign in

arXiv:math/9212202 [math.LO]AbstractReferencesReviewsResources

A large Pi-1-2 set absolute for set forcing

Sy D. Friedman

Published 1992-12-02Version 1

Let k be a definable L-cardinal. Then there is a set of reals X, class-generic over L, such that L(X) and L have the same cardinals, X has size k in L(X) and some pi-1-2 formula defines X in all set-generic extensions of L(X). Two corollaries, both assuming the consistency of an inaccessible: It is consistent for the Perfect Set Property to hold for boldface sigma-1-2 sets, yet fail for some lightface pi-1-2 set. It is consistent that the Perfect Set Property holds for boldface sigma-1-2 sets yet some lightface pi-1-2 wellordering of some set of reals has length aleph-1000.

Related articles: Most relevant | Search more
arXiv:1607.01625 [math.LO] (Published 2016-07-06)
On the set-generic multiverse
arXiv:math/9201249 [math.LO] (Published 1992-01-15)
Coding and reshaping when there are no sharps
arXiv:1402.4659 [math.LO] (Published 2014-02-19, updated 2014-11-30)
Force a set model of $Z_3$ + Harrington's Principle