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Proceedings of the American Mathematical Society
Proceedings of the American Mathematical Society
ISSN 1088-6826 (e) ISSN 0002-9939 (p)
     

On subspaces of pseudoradial spaces

Author(s): Alan Dow; Jinyuan Zhou
Journal: Proc. Amer. Math. Soc. 127 (1999), 1221-1230.
MSC (1991): Primary 54E35
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Abstract: A topological space $X$ is pseudoradial if each of its non closed subsets $A$ has a sequence (not necessarily with countable length) convergent to outside of $A$. We prove the following results concerning pseudoradial spaces and the spaces $\omega \cup \{p\}$, where $p$ is an ultrafilter on $\omega$:

(i) CH implies that, for every ultrafilter $p$ on $\omega$, $\omega \cup \{p\} $ is a subspace of some regular pseudoradial space.

(ii) There is a model in which, for each P-point $p$, $\omega \cup \{p\}$ cannot be embedded in a regular pseudoradial space while there is a point $q$ such that $\omega\cup\{q\}$ is a subspace of a zero-dimensional Hausdorff pseudoradial space.


References:

1.
A.V. Arhangel'ski[??]i, R. Isler, and G.Tironi. On pseudo-radial spaces. Comment. Math. Univ. Carolinae, 27(1):137-154, 1986.

2.
Bohuslav Balcar and Petr Simon. Disjoint refinement. In J.K. Monk and R. Bonnet, editors, Handbook of Boolean Algebra, chapter 9. Elsevier Science Publishers, B.V., 1989. CMP 21:10

3.
Mohamed Bekkali. Topics in Set Theory. Springer-Verlag, 1991. MR 92m:03070

4.
Alan Dow. The completion of $ \cal {P}(\omega)/\text{Fin}$ is not equal to the regular open algebra of $\beta{\mathbb{R}} \setminus {\mathbb{R}}$. to appear.

5.
Alan Dow and Jinyuan Zhou. Two real ultrafilters on $\omega$. on Topology and its Applications. to appear

6.
Kenneth Kunen. Set Theory. Elsevier Science Publishers, B.V., 1980. MR 82f:03001

7.
Peter J. Nyikos. Convergence in topology. In M. Hus\v{e}k and J. van Mill, editors, Recent Progress in General Topology, chapter 17. Elsevier Science Publishers B.V., 1992. CMP 93:15

8.
Saharon Shelah. Proper Forcing. Springer-Verlag, 1982. MR 84h:03002

9.
Jinyuan Zhou. On subspaces of pseudo-radial spaces. Comment. Math. Univ. Carolinae, 34(3):583-586, 1994. MR 94h:54003

10.
William S. Zwicker. ${P}_\kappa \lambda $ combinatorics I: Stationary coding sets rationalize the club filter. In Donald A. Martin James E. Baumgartner and Saharon Shelah, editors, Axiomatic Set Theory, pages 243-259. American Mathematical Society, 1984. MR 86e:03046


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Additional Information:

Alan Dow
Affiliation: Department of Mathematics, York University, 4700 Keele Street, North York, Ontario Canada M3J 1P3
Email: Alan.Dow@mathstat.yorku.ca

Jinyuan Zhou
Affiliation: Department of Mathematics, York University, 4700 Keele Street, North York, Ontario Canada M3J 1P3
Email: jzhou@spicer.com

DOI: 10.1090/S0002-9939-99-04628-6
PII: S 0002-9939(99)04628-6
Keywords: Forcing, CH, ultrafilter, zero-dimensional space, pseudoradial
Received by editor(s): March 17, 1997
Received by editor(s) in revised form: July 30, 1997
Communicated by: Carl Jockusch
Copyright of article: Copyright 1999, American Mathematical Society


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