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Completely nonmeasurable unions
Assume that no cardinal κ < 2 ω is quasi-measurable ( κ is quasi-measurable if there exists a κ -additive ideal of subsets of κ such that the Boolean algebra P ( κ )/ satisfies c.c.c.). We show that for a metrizable separable space X and a proper c.c.c. σ-ideal II of subsets of X that has a Borel...
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Published in: | Central European journal of mathematics 2010, Vol.8 (4), p.683-687 |
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Main Authors: | , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | Assume that no cardinal
κ
< 2
ω
is quasi-measurable (
κ
is quasi-measurable if there exists a
κ
-additive ideal
of subsets of
κ
such that the Boolean algebra
P
(
κ
)/
satisfies c.c.c.). We show that for a metrizable separable space
X
and a proper c.c.c. σ-ideal II of subsets of
X
that has a Borel base, each point-finite cover
⊆
of
X
contains uncountably many pairwise disjoint subfamilies
, with
-Bernstein unions ∪
(a subset
A
⊆
X
is
-Bernstein if
A
and
X
\
A
meet each Borel
-positive subset
B
⊆
X
). This result is a generalization of the Four Poles Theorem (see [1]) and results from [2] and [4]. |
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ISSN: | 1895-1074 2391-5455 1644-3616 2391-5455 |
DOI: | 10.2478/s11533-010-0038-z |