On the Existence of Strong Chains in $\wp(\omega_1)$/Fin
Koszmider, Piotr
J. Symbolic Logic, Tome 63 (1998) no. 1, p. 1055-1062 / Harvested from Project Euclid
$(X_\alpha : \alpha < \omega_2) \subset \wp(\omega_1)$ is a strong chain in $\wp(\omega_1)$/Fin if and only if $X_\beta - X_\alpha$ is finite and $X_\alpha - X_\beta$ is uncountable for each $\beta < \alpha < \omega_1$. We show that it is consistent that a strong chain in $\wp(\omega_1)$ exists. On the other hand we show that it is consistent that there is a strongly almost-disjoint family in $\wp(\omega_1)$ but no strong chain exists: $\square_{\omega_1}$ is used to construct a c.c.c forcing that adds a strong chain and Chang's Conjecture to prove that there is no strong chain.
Publié le : 1998-09-14
Classification: 
@article{1183745580,
     author = {Koszmider, Piotr},
     title = {On the Existence of Strong Chains in $\wp(\omega\_1)$/Fin},
     journal = {J. Symbolic Logic},
     volume = {63},
     number = {1},
     year = {1998},
     pages = { 1055-1062},
     language = {en},
     url = {http://dml.mathdoc.fr/item/1183745580}
}
Koszmider, Piotr. On the Existence of Strong Chains in $\wp(\omega_1)$/Fin. J. Symbolic Logic, Tome 63 (1998) no. 1, pp.  1055-1062. http://gdmltest.u-ga.fr/item/1183745580/