English

Selective game versions of countable tightness with bounded finite selections

General Topology 2016-04-01 v1 Combinatorics

Abstract

For a topological space XX and a point xXx \in X, consider the following game -- related to the property of XX being countably tight at xx. In each inning nωn\in\omega, the first player chooses a set AnA_n that clusters at xx, and then the second player picks a point anAna_n\in A_n; the second player is the winner if and only if x{an:nω}x\in\overline{\{a_n:n\in\omega\}}. In this work, we study variations of this game in which the second player is allowed to choose finitely many points per inning rather than one, but in which the number of points they are allowed to choose in each inning has been fixed in advance. Surprisingly, if the number of points allowed per inning is the same throughout the play, then all of the games obtained in this fashion are distinct. We also show that a new game is obtained if the number of points the second player is allowed to pick increases at each inning.

Keywords

Cite

@article{arxiv.1603.09715,
  title  = {Selective game versions of countable tightness with bounded finite selections},
  author = {Leandro F. Aurichi and Angelo Bella and Rodrigo R. Dias},
  journal= {arXiv preprint arXiv:1603.09715},
  year   = {2016}
}