Metamath Proof Explorer


Theorem cnrmnrm

Description: A completely normal space is normal. (Contributed by Mario Carneiro, 26-Aug-2015)

Ref Expression
Assertion cnrmnrm ( 𝐽 ∈ CNrm → 𝐽 ∈ Nrm )

Proof

Step Hyp Ref Expression
1 eqid ⊢ ∪ 𝐽 = ∪ 𝐽
2 1 restid ⊢ ( 𝐽 ∈ CNrm → ( 𝐽 ↾t ∪ 𝐽 ) = 𝐽 )
3 uniexg ⊢ ( 𝐽 ∈ CNrm → ∪ 𝐽 ∈ V )
4 cnrmi ⊢ ( ( 𝐽 ∈ CNrm ∧ ∪ 𝐽 ∈ V ) → ( 𝐽 ↾t ∪ 𝐽 ) ∈ Nrm )
5 3 4 mpdan ⊢ ( 𝐽 ∈ CNrm → ( 𝐽 ↾t ∪ 𝐽 ) ∈ Nrm )
6 2 5 eqeltrrd ⊢ ( 𝐽 ∈ CNrm → 𝐽 ∈ Nrm )