Metamath Proof Explorer


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