Switch to: Citations

Add references

You must login to add references.
  1. The lottery preparation.Joel David Hamkins - 2000 - Annals of Pure and Applied Logic 101 (2-3):103-146.
    The lottery preparation, a new general kind of Laver preparation, works uniformly with supercompact cardinals, strongly compact cardinals, strong cardinals, measurable cardinals, or what have you. And like the Laver preparation, the lottery preparation makes these cardinals indestructible by various kinds of further forcing. A supercompact cardinal κ, for example, becomes fully indestructible by <κ-directed closed forcing; a strong cardinal κ becomes indestructible by κ-strategically closed forcing; and a strongly compact cardinal κ becomes indestructible by, among others, the forcing to (...)
    Download  
     
    Export citation  
     
    Bookmark   63 citations  
  • Destruction or preservation as you like it.Joel David Hamkins - 1998 - Annals of Pure and Applied Logic 91 (2-3):191-229.
    The Gap Forcing Theorem, a key contribution of this paper, implies essentially that after any reverse Easton iteration of closed forcing, such as the Laver preparation, every supercompactness measure on a supercompact cardinal extends a measure from the ground model. Thus, such forcing can create no new supercompact cardinals, and, if the GCH holds, neither can it increase the degree of supercompactness of any cardinal; in particular, it can create no new measurable cardinals. In a crescendo of what I call (...)
    Download  
     
    Export citation  
     
    Bookmark   19 citations  
  • On the Hamkins approximation property.William J. Mitchell - 2006 - Annals of Pure and Applied Logic 144 (1-3):126-129.
    We give a short proof of a lemma which generalizes both the main lemma from the original construction in the author’s thesis of a model with no ω2-Aronszajn trees, and also the “Key Lemma” in Hamkins’ gap forcing theorems. The new lemma directly yields Hamkins’ newer lemma stating that certain forcing notions have the approximation property.
    Download  
     
    Export citation  
     
    Bookmark   15 citations  
  • Strongly unfoldable cardinals made indestructible.Thomas A. Johnstone - 2008 - Journal of Symbolic Logic 73 (4):1215-1248.
    I provide indestructibility results for large cardinals consistent with V = L, such as weakly compact, indescribable and strongly unfoldable cardinals. The Main Theorem shows that any strongly unfoldable cardinal κ can be made indestructible by <κ-closed. κ-proper forcing. This class of posets includes for instance all <κ-closed posets that are either κ -c.c, or ≤κ-strategically closed as well as finite iterations of such posets. Since strongly unfoldable cardinals strengthen both indescribable and weakly compact cardinals, the Main Theorem therefore makes (...)
    Download  
     
    Export citation  
     
    Bookmark   13 citations  
  • Small forcing makes any cardinal superdestructible.Joel Hamkins - 1998 - Journal of Symbolic Logic 63 (1):51-58.
    Small forcing always ruins the indestructibility of an indestructible supercompact cardinal. In fact, after small forcing, any cardinal κ becomes superdestructible--any further <κ--closed forcing which adds a subset to κ will destroy the measurability, even the weak compactness, of κ. Nevertheless, after small forcing indestructible cardinals remain resurrectible, but never strongly resurrectible.
    Download  
     
    Export citation  
     
    Bookmark   15 citations  
  • Stacking mice.Ronald Jensen, Ernest Schimmerling, Ralf Schindler & John Steel - 2009 - Journal of Symbolic Logic 74 (1):315-335.
    We show that either of the following hypotheses imply that there is an inner model with a proper class of strong cardinals and a proper class of Woodin cardinals. 1) There is a countably closed cardinal k ≥ N₃ such that □k and □(k) fail. 2) There is a cardinal k such that k is weakly compact in the generic extension by Col(k, k⁺). Of special interest is 1) with k = N₃ since it follows from PFA by theorems of (...)
    Download  
     
    Export citation  
     
    Bookmark   12 citations  
  • Indescribable cardinals and elementary embeddings.Kai Hauser - 1991 - Journal of Symbolic Logic 56 (2):439-457.
    Download  
     
    Export citation  
     
    Bookmark   15 citations  
  • Diamond (on the regulars) can fail at any strongly unfoldable cardinal.Mirna Džamonja & Joel David Hamkins - 2006 - Annals of Pure and Applied Logic 144 (1-3):83-95.
    If κ is any strongly unfoldable cardinal, then this is preserved in a forcing extension in which κ fails. This result continues the progression of the corresponding results for weakly compact cardinals, due to Woodin, and for indescribable cardinals, due to Hauser.
    Download  
     
    Export citation  
     
    Bookmark   10 citations  
  • Chains of end elementary extensions of models of set theory.Andres Villaveces - 1998 - Journal of Symbolic Logic 63 (3):1116-1136.
    Large cardinals arising from the existence of arbitrarily long end elementary extension chains over models of set theory are studied here. In particular, we show that the large cardinals obtained in this fashion (`unfoldable cardinals') lie in the boundary of the propositions consistent with `V = L' and the existence of 0 ♯ . We also provide an `embedding characterisation' of the unfoldable cardinals and study their preservation and destruction by various forcing constructions.
    Download  
     
    Export citation  
     
    Bookmark   9 citations  
  • Indestructible Weakly Compact Cardinals and the Necessity of Supercompactness for Certain Proof Schemata.J. D. Hamkins & A. W. Apter - 2001 - Mathematical Logic Quarterly 47 (4):563-572.
    We show that if the weak compactness of a cardinal is made indestructible by means of any preparatory forcing of a certain general type, including any forcing naively resembling the Laver preparation, then the cardinal was originally supercompact. We then apply this theorem to show that the hypothesis of supercompactness is necessary for certain proof schemata.
    Download  
     
    Export citation  
     
    Bookmark   7 citations  
  • Kurepa trees and Namba forcing.Bernhard König & Yasuo Yoshinobu - 2012 - Journal of Symbolic Logic 77 (4):1281-1290.
    We show that strongly compact cardinals and MM are sensitive to $\lambda$-closed forcings for arbitrarily large $\lambda$. This is done by adding ‘regressive' $\lambda$-Kurepa trees in either case. We argue that the destruction of regressive Kurepa trees requires a non-standard application of MM. As a corollary, we find a consistent example of an $\omega_2$-closed poset that is not forcing equivalent to any $\omega_2$-directed-closed poset.
    Download  
     
    Export citation  
     
    Bookmark   4 citations  
  • Unfoldable cardinals and the GCH.Joel Hamkins - 2001 - Journal of Symbolic Logic 66 (3):1186-1198.
    Unfoldable cardinals are preserved by fast function forcing and the Laver-like preparations that fast functions support. These iterations show, by set-forcing over any model of ZFC, that any given unfoldable cardinal κ can be made indestructible by the forcing to add any number of Cohen subsets to κ.
    Download  
     
    Export citation  
     
    Bookmark   6 citations  
  • An equiconsistency for universal indestructibility.Arthur W. Apter & Grigor Sargsyan - 2010 - Journal of Symbolic Logic 75 (1):314-322.
    We obtain an equiconsistency for a weak form of universal indestructibility for strongness. The equiconsistency is relative to a cardinal weaker in consistency strength than a Woodin cardinal. Stewart Baldwin's notion of hyperstrong cardinal. We also briefly indicate how our methods are applicable to universal indestructibility for supercompactness and strong compactness.
    Download  
     
    Export citation  
     
    Bookmark   4 citations