Metamath Proof Explorer


Theorem cmptop

Description: A compact topology is a topology. (Contributed by Jeff Hankins, 29-Jun-2009)

Ref Expression
Assertion cmptop ⊢ J ∈ Comp → J ∈ Top

Proof

Step Hyp Ref Expression
1 eqid ⊢ ⋃ J = ⋃ J
2 1 iscmp ⊢ J ∈ Comp ↔ J ∈ Top ∧ ∀ r ∈ 𝒫 J ⋃ J = ⋃ r → ∃ s ∈ 𝒫 r ∩ Fin ⋃ J = ⋃ s
3 2 simplbi ⊢ J ∈ Comp → J ∈ Top