Interior of a subset
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Revision 382
7/10/2026, 1:29:46 PM · Ancient Tree
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The interior of a [[subset|subset]] $A$ of a [[Topological space|topological space]] $X$ is...1
The interior $\operatorname{int}(A)$ of a [[subset|subset]] $A$ of a [[Topological space|topological space]] $X$ is the largest [[Open set|open set]] contained in $A$. 2
It can be shown that it is the union of all open sets contained in $A$ :3
$$\operatorname{int}(A)=\bigcup\{U \subseteq X: U \text { open, } U \subseteq A\}$$Revision 189
7/2/2026, 1:22:12 PM · Ancient Tree
Concept created
The interior of a [[subset|subset]] $A$ of a [[Topological space|topological space]] $X$ is...