Spector Forcing
Henle, J. M.
J. Symbolic Logic, Tome 49 (1984) no. 1, p. 542-554 / Harvested from Project Euclid
Forcing with $\lbrack\kappa\rbrack^\kappa$ over a model of set theory with a strong partition cardinal, M. Spector produced a generic ultrafilter $G$ on $\kappa$ such that $\kappa^\kappa/G$ is not well-founded. Theorem. Let $G$ be Spector-generic over a model $M$ of $ZF + DC + \kappa \rightarrow (\kappa)^\kappa_\alpha, \kappa > \omega$, for all $\alpha < \kappa$. 1) Every cardinal (well-ordered or not) of $M$ is a cardinal of $M\lbrack G\rbrack$. 2) If $A \in M\lbrack G\rbrack$ is a well-ordered subset of $M$, then $A \in M$. Let $\Phi = \kappa^\kappa/G$. 3) There is an ultrafilter $U$ on $\Phi$ such that every member of $U$ has a subset of type $\Phi$, and the intersection of any well-ordered subset of $U$ is in $U$. 4) $\Phi$ satisfies $\Phi \rightarrow (\Phi)^\alpha_\beta$ for all $\alpha < \aleph_1$ and all ordinals $\beta$. 5) There is a linear order $\Phi'$ with property 3) above which is not "weakly compact", i.e., $\Phi' \nrightarrow (\Phi')^2$.
Publié le : 1984-06-14
Classification: 
@article{1183741554,
     author = {Henle, J. M.},
     title = {Spector Forcing},
     journal = {J. Symbolic Logic},
     volume = {49},
     number = {1},
     year = {1984},
     pages = { 542-554},
     language = {en},
     url = {http://dml.mathdoc.fr/item/1183741554}
}
Henle, J. M. Spector Forcing. J. Symbolic Logic, Tome 49 (1984) no. 1, pp.  542-554. http://gdmltest.u-ga.fr/item/1183741554/