Abstract
Inspired by work of Scheepers and Tall, we use properties de-fined by topological games to provide bounds for the cardinality of topological spaces. We obtain a partial answer to an old question of Bell, Ginsburg and Woods regarding the cardinality of weakly Lindelöf first-countable regular spaces and answer a question recently asked by Babinkostova, Pansera and Scheepers. In the second part of the paper we study a game-theoretic variant of the countable chain condition, introduced by Daniels, Kunen and Zhou in 1994. We prove that it is equivalent to countable π-weight for spaces having countable local π-weight at every point, and exploit it to give a new proof of Shapirovskii's classical bound on the number of regular open sets of a regular topological space.
| Original language | English |
|---|---|
| Pages (from-to) | 1063-1077 |
| Number of pages | 15 |
| Journal | Houston Journal of Mathematics |
| Volume | 41 |
| Issue number | 3 |
| State | Published - 1 Jan 2015 |
| Externally published | Yes |
Keywords
- Almost Lindelöf
- Arhangel'skii Theorem
- Infinite games
- Lindelöf
- Relatively H-closed
- Weakly Lindelöf
ASJC Scopus subject areas
- General Mathematics