Making the Hyperreal Line Both Saturated and Complete
Keisler, H. Jerome ; Schmerl, James H.
J. Symbolic Logic, Tome 56 (1991) no. 1, p. 1016-1025 / Harvested from Project Euclid
In a nonstandard universe, the $\kappa$-saturation property states that any family of fewer than $\kappa$ internal sets with the finite intersection property has a nonempty intersection. An ordered field $F$ is said to have the $\lambda$-Bolzano-Weierstrass property iff $F$ has cofinality $\lambda$ and every bounded $\lambda$-sequence in $F$ has a convergent $\lambda$-subsequence. We show that if $\kappa < \lambda$ are uncountable regular cardinals and $\beta^\alpha < \lambda$ whenever $\alpha < \kappa$ and $\beta < \lambda$, then there is a $\kappa$-saturated nonstandard universe in which the hyperreal numbers have the $\lambda$-Bolzano-Weierstrass property. The result also applies to certain fragments of set theory and second order arithmetic.
Publié le : 1991-09-15
Classification: 
@article{1183743748,
     author = {Keisler, H. Jerome and Schmerl, James H.},
     title = {Making the Hyperreal Line Both Saturated and Complete},
     journal = {J. Symbolic Logic},
     volume = {56},
     number = {1},
     year = {1991},
     pages = { 1016-1025},
     language = {en},
     url = {http://dml.mathdoc.fr/item/1183743748}
}
Keisler, H. Jerome; Schmerl, James H. Making the Hyperreal Line Both Saturated and Complete. J. Symbolic Logic, Tome 56 (1991) no. 1, pp.  1016-1025. http://gdmltest.u-ga.fr/item/1183743748/