If $X$ is normal and $F_1$, $F_2$ are disjoint closed subsets, then there exist open subsets $W_1$ ⊃ $F_1$, $W_2$ ⊃ $F_2$, whose closures are disjoint

score 81 · Answer 13 · 2026-03-25 07:05:12

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Example 2, Sec. 31, in Munkres' TOPOLOGY, 2nd ed: Normality of $\mathbb{R}_l$ --- Why are these two sets disjoint?

Published on 25 Mar 2026 - 7:05

score 888 · Answer 14 · 2019-06-02 08:29:43

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Separatedness of open subscheme of affine schemes

Published on 02 Jun 2019 - 8:29

score 74 · Answer 15 · 2019-06-13 05:29:03

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$X$ is regular iff $Y$ is regular

Published on 13 Jun 2019 - 5:29

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If $X$ is normal and $F_1$, $F_2$ are disjoint closed subsets, then there exist open subsets $W_1$ ⊃ $F_1$, $W_2$ ⊃ $F_2$, whose closures are disjoint

Example 2, Sec. 31, in Munkres' TOPOLOGY, 2nd ed: Normality of $\mathbb{R}_l$ --- Why are these two sets disjoint?

Separatedness of open subscheme of affine schemes

$X$ is regular iff $Y$ is regular

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