Pełnotekstowe zasoby PLDML oraz innych baz dziedzinowych są już dostępne w nowej Bibliotece Nauki.
Zapraszamy na https://bibliotekanauki.pl
Preferencje help
Polish version English version Język
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 4

Liczba wyników na stronie
first rewind previous Strona / 1 next fast forward last

Wyniki wyszukiwania

help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 1 next fast forward last
1
Content available remote

Combinatorics of open covers (III): games, Cp (X)

100%
Scheepers M.
Fundamenta Mathematicae
|
1997
|
tom 152
|
nr 3
231-254
EN
Some of the covering properties of spaces as defined in Parts I and II are here characterized by games. These results, applied to function spaces $C_p(X)$ of countable tightness, give new characterizations of countable fan tightness and countable strong fan tightness. In particular, each of these properties is characterized by a Ramseyan theorem.
2
Content available remote

Lindelöf indestructibility, topological games and selection principles

63%
Scheepers M., Tall F.
Fundamenta Mathematicae
|
2010
|
tom 210
|
nr 1
1-46
EN
Arhangel'skii proved that if a first countable Hausdorff space is Lindelöf, then its cardinality is at most $2^{ℵ₀}$. Such a clean upper bound for Lindelöf spaces in the larger class of spaces whose points are $G_{δ}$ has been more elusive. In this paper we continue the agenda started by the second author, [Topology Appl. 63 (1995)], of considering the cardinality problem for spaces satisfying stronger versions of the Lindelöf property. Infinite games and selection principles, especially the Rothberger property, are essential tools in our investigations.
3
Content available remote

Errata to "Lindelöf indestructibility, topological games and selection principles" (Fund. Math. 210 (2010), 1-46)

63%
Scheepers M., Tall F.
Fundamenta Mathematicae
|
2014
|
tom 224
|
nr 2
203-204
EN
In [Fund. Math. 210 (2010), 1-46] we claimed the truth of two statements, one now known to be false and a second lacking a proof. In this "Errata" we report these matters in the interest of setting the record straight on the status of these claims.
4
Content available remote

Combinatorics of open covers (VII): Groupability

63%
Kočinac L., Scheepers M.
Fundamenta Mathematicae
|
2003
|
tom 179
|
nr 2
131-155
EN
We use Ramseyan partition relations to characterize: ∙ the classical covering property of Hurewicz; ∙ the covering property of Gerlits and Nagy; ∙ the combinatorial cardinal numbers 𝔟 and add(ℳ ). Let X be a $T_{31/2}$-space. In [9] we showed that $C_{p}(X)$ has countable strong fan tightness as well as the Reznichenko property if, and only if, all finite powers of X have the Gerlits-Nagy covering property. Now we show that the following are equivalent: 1. $C_{p}(X)$ has countable fan tightness and the Reznichenko property. 2. All finite powers of X have the Hurewicz property. We show that for $C_{p}(X)$ the combination of countable fan tightness with the Reznichenko property is characterized by a Ramseyan partition relation. Extending the work in [9], we give an analogous Ramseyan characterization for the combination of countable strong fan tightness with the Reznichenko property on $C_{p}(X)$.
first rewind previous Strona / 1 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.