Metamath Proof Explorer


Theorem lpsscls

Description: The limit points of a subset are included in the subset's closure. (Contributed by NM, 26-Feb-2007)

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

Proof

Step Hyp Ref Expression
1 lpfval.1 ⊢ X = ⋃ J
2 1 lpval ⊢ J ∈ Top ∧ S ⊆ X → limPt ⁡ J ⁡ S = x | x ∈ cls ⁡ J ⁡ S ∖ x
3 difss ⊢ S ∖ x ⊆ S
4 1 clsss ⊢ J ∈ Top ∧ S ⊆ X ∧ S ∖ x ⊆ S → cls ⁡ J ⁡ S ∖ x ⊆ cls ⁡ J ⁡ S
5 3 4 mp3an3 ⊢ J ∈ Top ∧ S ⊆ X → cls ⁡ J ⁡ S ∖ x ⊆ cls ⁡ J ⁡ S
6 5 sseld ⊢ J ∈ Top ∧ S ⊆ X → x ∈ cls ⁡ J ⁡ S ∖ x → x ∈ cls ⁡ J ⁡ S
7 6 abssdv ⊢ J ∈ Top ∧ S ⊆ X → x | x ∈ cls ⁡ J ⁡ S ∖ x ⊆ cls ⁡ J ⁡ S
8 2 7 eqsstrd ⊢ J ∈ Top ∧ S ⊆ X → limPt ⁡ J ⁡ S ⊆ cls ⁡ J ⁡ S