Metamath Proof Explorer


Theorem perflp

Description: The limit points of a perfect space. (Contributed by Mario Carneiro, 24-Dec-2016)

Ref Expression
Hypothesis lpfval.1 ⊢ X = ⋃ J
Assertion perflp ⊢ J ∈ Perf → limPt ⁡ J ⁡ X = X

Proof

Step Hyp Ref Expression
1 lpfval.1 ⊢ X = ⋃ J
2 1 isperf ⊢ J ∈ Perf ↔ J ∈ Top ∧ limPt ⁡ J ⁡ X = X
3 2 simprbi ⊢ J ∈ Perf → limPt ⁡ J ⁡ X = X