Backwards Easton Forcing and $0^#$
Stanley, M. C.
J. Symbolic Logic, Tome 53 (1988) no. 1, p. 809-833 / Harvested from Project Euclid
It is shown that if $\kappa$ is an uncountable successor cardinal in $L\lbrack 0^\sharp\rbrack$, then there is a normal tree $\mathbf{T} \in L \lbrack 0^\sharp\rbrack$ of height $\kappa$ such that $0^\sharp \not\in L\lbrack\mathbf{T}\rbrack$. Yet $\mathbf{T}$ is $<\kappa$-distributive in $L\lbrack 0^\sharp\rbrack$. A proper class version of this theorem yields an analogous $L\lbrack 0^\sharp\rbrack$-definable tree such that distinct branches in the presence of $0^\sharp$ collapse the universe. A heretofore unutilized method for constructing in $L\lbrack 0^\sharp\rbrack$ generic objects for certain $L$-definable forcings and "exotic sequences", combinatorial principles introduced by C. Gray, are used in constructing these trees.
Publié le : 1988-09-14
Classification: 
@article{1183742721,
     author = {Stanley, M. C.},
     title = {Backwards Easton Forcing and $0^\#$},
     journal = {J. Symbolic Logic},
     volume = {53},
     number = {1},
     year = {1988},
     pages = { 809-833},
     language = {en},
     url = {http://dml.mathdoc.fr/item/1183742721}
}
Stanley, M. C. Backwards Easton Forcing and $0^#$. J. Symbolic Logic, Tome 53 (1988) no. 1, pp.  809-833. http://gdmltest.u-ga.fr/item/1183742721/