Article contents
INDESTRUCTIBILITY OF THE TREE PROPERTY
Published online by Cambridge University Press: 16 September 2019
Abstract
In the first part of the article, we show that if $\omega \le \kappa < \lambda$ are cardinals,
${\kappa ^{ < \kappa }} = \kappa$, and λ is weakly compact, then in
$V\left[M {\left( {\kappa ,\lambda } \right)} \right]$ the tree property at
$$\lambda = \left( {\kappa ^{ + + } } \right)^{V\left[ {\left( {\kappa ,\lambda } \right)} \right]} $$ is indestructible under all
${\kappa ^ + }$-cc forcing notions which live in
$V\left[ {{\rm{Add}}\left( {\kappa ,\lambda } \right)} \right]$, where
${\rm{Add}}\left( {\kappa ,\lambda } \right)$ is the Cohen forcing for adding λ-many subsets of κ and
$\left( {\kappa ,\lambda } \right)$ is the standard Mitchell forcing for obtaining the tree property at
$\lambda = \left( {\kappa ^{ + + } } \right)^{V\left[ {\left( {\kappa ,\lambda } \right)} \right]} $. This result has direct applications to Prikry-type forcing notions and generalized cardinal invariants. In the second part, we assume that λ is supercompact and generalize the construction and obtain a model
${V^{\rm{*}}}$, a generic extension of V, in which the tree property at
${\left( {{\kappa ^{ + + }}} \right)^{{V^{\rm{*}}}}}$ is indestructible under all
${\kappa ^ + }$-cc forcing notions living in
$V\left[ {{\rm{Add}}\left( {\kappa ,\lambda } \right)} \right]$, and in addition under all forcing notions living in
${V^{\rm{*}}}$ which are
${\kappa ^ + }$-closed and “liftable” in a prescribed sense (such as
${\kappa ^{ + + }}$-directed closed forcings or well-met forcings which are
${\kappa ^{ + + }}$-closed with the greatest lower bounds).
- Type
- Articles
- Information
- Copyright
- Copyright © The Association for Symbolic Logic 2019
References
REFERENCES











- 4
- Cited by