Title
Collapsing functions
Abstract
1 )+, then there is no precipitous ideal on ω1. We show that a collapsing function for ω2 can be added by forcing. We define what it means to be a weakly ω1-Erdos cardinal and show that in L(E), there is a collapsing function for λ iff λ is less than the least weakly ω1-Erdos cardinal. As a corollary to our results and a theorem of Neeman, the existence of a Woodin limit of Woodin cardinals does not imply the existence of precipitous ideals on ω1. We also show that the following statements hold in L(E). The least cardinal λ with the Chang property (λ, ω1) (ω1 ,ω ) is equal to the least ω1-Erdos cardinal. In particular, if j is a generic elementary embedding that arises from non-stationary tower forcing up to a Woodin cardinal, then the minimum possible value of j(ω1) is the least ω1-Erdos cardinal.
Year
DOI
Venue
2004
10.1002/malq.200310069
Math. Log. Q.
Keywords
DocType
Volume
large cardinal,precipitous ideal,core model. msc 2000 03e55
Journal
50
Issue
Citations 
PageRank 
1
3
0.73
References 
Authors
1
2
Name
Order
Citations
PageRank
Ernest Schimmerling130.73
Boban Velickovic2476.80