Metamath Proof Explorer


Theorem lpss

Description: The limit points of a subset are included in the base set. (Contributed by NM, 9-Nov-2007)

Ref Expression
Hypothesis lpfval.1 ⊢ X = ⋃ J
Assertion lpss ⊢ J ∈ Top ∧ S ⊆ X → limPt ⁡ J ⁡ S ⊆ X

Proof

Step Hyp Ref Expression
1 lpfval.1 ⊢ X = ⋃ J
2 1 lpsscls ⊢ J ∈ Top ∧ S ⊆ X → limPt ⁡ J ⁡ S ⊆ cls ⁡ J ⁡ S
3 1 clsss3 ⊢ J ∈ Top ∧ S ⊆ X → cls ⁡ J ⁡ S ⊆ X
4 2 3 sstrd ⊢ J ∈ Top ∧ S ⊆ X → limPt ⁡ J ⁡ S ⊆ X