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Asaf Karagila ♦
Asaf Karagila ♦
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Let $X$ be a countably infniteinfinite (or larger) set with the cofinite topology. for every $x\in X$ is there exists a family $\xi\subset\tau$ such that $\{x\}=\bigcap\xi $$\lbrace x\rbrace=\bigcap\xi $ ? If the answer is yes, then what is the cardinality of $\xi$ ?

Let $X$ be a countably infnite (or larger) set with the cofinite topology. for every $x\in X$ is there exists a family $\xi\subset\tau$ such that $\{x\}=\bigcap\xi $ ? If the answer is yes, then what is the cardinality of $\xi$ ?

Let $X$ be a countably infinite (or larger) set with the cofinite topology. for every $x\in X$ is there exists a family $\xi\subset\tau$ such that $\lbrace x\rbrace=\bigcap\xi $ ? If the answer is yes, then what is the cardinality of $\xi$ ?

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Empty.Subset
Empty.Subset
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Let $X$ be a countably infnite (or larger) set with the cofinite topology. for every $x\in X$ is there exists a family $\xi\subset\tau$ such that $\{x\}=\bigcap \xi$$\{x\}=\bigcap\xi $ ? If the answer is yes, then what is the cardinality of $\xi$ ?

Let $X$ be a countably infnite (or larger) set with the cofinite topology. for every $x\in X$ is there exists a family $\xi\subset\tau$ such that $\{x\}=\bigcap \xi$ ? If the answer is yes, then what is the cardinality of $\xi$ ?

Let $X$ be a countably infnite (or larger) set with the cofinite topology. for every $x\in X$ is there exists a family $\xi\subset\tau$ such that $\{x\}=\bigcap\xi $ ? If the answer is yes, then what is the cardinality of $\xi$ ?

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Empty.Subset
Empty.Subset
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A question on cofinite topology.

Let $X$ be a countably infnite (or larger) set with the cofinite topology. for every $x\in X$ is there exists a family $\xi\subset\tau$ such that $\{x\}=\bigcap \xi$ ? If the answer is yes, then what is the cardinality of $\xi$ ?