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 )