arXiv subjects
Publications and source records attributed to Leandro F. Aurichi.
In these notes we introduce and investigate two new games called R-nw-selective game and the M-nw-selective game. These games naturally arise from the corresponding selection principles involving networks introduced in \cite{BG}.
We present a new variation of the classical selection principles $\mathsf{S}_\mathrm{k}(\mathcal A, \mathcal B)$ ($k\in\mathbb N$) and $\mathsf{S}_\mathrm{fin}(\mathcal A, \mathcal B)$ that formally lies between these two properties. As in the case of the classical selection principles, we also obtain a new variation of topological games and discuss how new topological properties may emerge in the specific cases of covering and tightness.
We present an internal characterization for the productively Lindelöf property, thus answering a long-standing problem attributed to Tamano. We also present some results about the relation Alster spaces vs. productively Lindelöf spaces.
The main goal of the paper is the full proof of a cardinal inequality for a space with points $G_δ$, obtained with the help of a long version of the Menger game. This result, which improves a similar one of Scheepers and Tall, was already established by the authors under the Continuum Hypothesis. The paper is completed by few remarks on a long version of the tightness game.
We present a selection principle $S_1(\mathcal{O},\mathcal{H})$ that characterizes the $G_δ$-diagonal property. We also present a topological game induced by this selection principle and we study the relations between this game and the $G_δ$-property. Finally, we give some applications and examples.
For a topological space $X$ and a point $x \in X$, consider the following game -- related to the property of $X$ being countably tight at $x$. In each inning $n\inω$, the first player chooses a set $A_n$ that clusters at $x$, and then the second player picks a point $a_n\in A_n$; the second player is the winner if and only if $x\in\overline{\{a_n:n\inω\}}$. 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.
We try to characterize those Tychonoff spaces $X$ such that $βX \setminus X$ has the Menger property.
The main purpose of the paper is the proof of a cardinal inequality for a space with points $G_δ$, obtained with the help of a long version of the Menger game. This result improves a similar one of Scheepers and Tall.
The two main results of this work are the following: if a space $X$ is such that player II has a winning strategy in the game $\gone(Ω_x, Ω_x)$ for every $x \in X$, then $X$ is productively countably tight. On the other hand, if a space is productively countably tight, then $\sone(Ω_x, Ω_x)$ holds for every $x \in X$. With these results, several other results follow, using some characterizations made by Uspenskii and Scheepers.
In this paper we study connections between topological games such as Rothberger, Menger and compact-open, and relate these games to properties involving covers by G_δ subsets. The results include: (1) If Two has a winning strategy in the Menger game on a regular space X, then X is an Alster space. (2) If Two has a winning strategy in the Rothberger game on a topological space X, then the G_δ-topology on X is Lindelof. (3) The Menger game and the compact-open game are (consistently) not dual.
We discuss relationships in Lindelof spaces among the properties "indestructible", "productive", "D", and related properties.