Some Remarks on Generalized Martin's Axiom

Z. Spasojević

Publications de l'Institut Mathématique, _N_S_57 (1995) no. 71, p. 135 .

Résumé

Let $GMA$ denote that if ${\Bbb P}$ is well-met, strongly $\omega_1$-closed and $\omega_1$-centered partial order and ${\Cal D}$ a family of $2^{\omega_1}$ dense subsets of ${\Bbb P}$: then there is a filter $G\subseteq {\Bbb P}$ which meets every member of ${\Cal D}$. The consistency of $2^\omega = \omega_1 + 2^{\omega_1}>\omega_2 + GMA$ was proved by Baumgartner [1] and in [13] many of its consequences were considered. In this paper we give a consequence and present an independence result. Namely, we prove that, as a consequence of $2^\omega = \omega_1 + 2^{\omega_1}>\omega_2 + GMA$, every $\leq^*$-increasing $\omega_2$-sequence in $(\omega_1^{\omega_1},\leq^*)$ is a lower half of some $(\omega_2,\omega_2)$-gap and show that the existence of an $\omega_2$-Kurepa tree is consistent with and independent of $2^\omega = \omega_1 + 2^{\omega_1}>\omega_2 + GMA$.

Détail

Classification : 03E35