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BASIC TOPOLOGY
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Separated spaces: T0, T1, T2 (Hausdorff) ...
pnrmnrm
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Metamath Proof Explorer
Ascii
Unicode
Theorem
pnrmnrm
Description:
A perfectly normal space is normal.
(Contributed by
Mario Carneiro
, 26-Aug-2015)
Ref
Expression
Assertion
pnrmnrm
⊢
J
∈
PNrm
→
J
∈
Nrm
Proof
Step
Hyp
Ref
Expression
1
ispnrm
⊢
J
∈
PNrm
↔
J
∈
Nrm
∧
Clsd
⁡
J
⊆
ran
⁡
x
∈
J
ℕ
⟼
⋂
ran
⁡
x
2
1
simplbi
⊢
J
∈
PNrm
→
J
∈
Nrm