Closed set

$\textbf{Closed set}$ Let $X$ be a topological space. A subset $A\subset X$ is called closed if $X\setminus A$ is open.
$\textbf{Closed set}$ Let $X$ be a topological space. A subset $A\subset X$ is called closed if $X\setminus A$ is open.
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𝐂𝐥𝐨𝐬𝐞𝐝 𝐬𝐞𝐭 Let 𝑋 be a topological space. A subset 𝐴⊂𝑋 is called closed if 𝑋∖𝐴 is open.
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