Metamath Proof Explorer


Theorem perftop

Description: A perfect space is a topology. (Contributed by Mario Carneiro, 25-Dec-2016)

Ref Expression
Assertion perftop ( 𝐽 ∈ Perf → 𝐽 ∈ Top )

Proof

Step Hyp Ref Expression
1 eqid ⊢ ∪ 𝐽 = ∪ 𝐽
2 1 isperf ⊢ ( 𝐽 ∈ Perf ↔ ( 𝐽 ∈ Top ∧ ( ( limPt ‘ 𝐽 ) ‘ ∪ 𝐽 ) = ∪ 𝐽 ) )
3 2 simplbi ⊢ ( 𝐽 ∈ Perf → 𝐽 ∈ Top )