On quasi-p-bounded subsets
Colloquium Mathematicum, Tome 80 (1999) no. 2, pp. 175-189
Voir la notice de l'article provenant de la source Institute of Mathematics Polish Academy of Sciences
The notion of quasi-p-boundedness for p ∈ $ω^*$ is introduced and investigated. We characterize quasi-p-pseudocompact subsets of β(ω) containing ω, and we show that the concepts of RK-compatible ultrafilter and P-point in $ω^*$ can be defined in terms of quasi-p-pseudocompactness. For p ∈ $ω^*$, we prove that a subset B of a space X is quasi-p-bounded in X if and only if B × $P_{RK}(p)$ is bounded in X × $P_{RK}(p)$, if and only if $cl_{β(X × P_{RK}(p))}(B× P_{RK}(p)) = cl_{βX} B × β(ω)$, where $P_{RK}(p)$ is the set of Rudin-Keisler predecessors of p.
Keywords:
free ultrafilter, P-point, (quasi)-p-pseudocompact space, Rudin-Keisler pre-order, p-limit point, (quasi)-p-bounded subset, bounded subset
Affiliations des auteurs :
M. Sanchis 1 ; A. Tamariz-Mascarúa 1
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author = {M. Sanchis and A. Tamariz-Mascar\'ua},
title = {On quasi-p-bounded subsets},
journal = {Colloquium Mathematicum},
pages = {175--189},
publisher = {mathdoc},
volume = {80},
number = {2},
year = {1999},
doi = {10.4064/cm-80-2-175-189},
language = {en},
url = {http://geodesic.mathdoc.fr/articles/10.4064/cm-80-2-175-189/}
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TY - JOUR AU - M. Sanchis AU - A. Tamariz-Mascarúa TI - On quasi-p-bounded subsets JO - Colloquium Mathematicum PY - 1999 SP - 175 EP - 189 VL - 80 IS - 2 PB - mathdoc UR - http://geodesic.mathdoc.fr/articles/10.4064/cm-80-2-175-189/ DO - 10.4064/cm-80-2-175-189 LA - en ID - 10_4064_cm_80_2_175_189 ER -
M. Sanchis; A. Tamariz-Mascarúa. On quasi-p-bounded subsets. Colloquium Mathematicum, Tome 80 (1999) no. 2, pp. 175-189. doi: 10.4064/cm-80-2-175-189
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