Metamath Proof Explorer


Theorem lmcld

Description: Any convergent sequence of points in a closed subset of a topological space converges to a point in the set. (Contributed by Mario Carneiro, 30-Dec-2013)

Ref Expression
Hypotheses lmff.1 ⊢ Z = ℤ ≥ M
lmff.3 ⊢ φ → J ∈ TopOn ⁡ X
lmff.4 ⊢ φ → M ∈ ℤ
lmcls.5 ⊢ φ → F ⇝t ⁡ J P
lmcls.7 ⊢ φ ∧ k ∈ Z → F ⁡ k ∈ S
lmcld.8 ⊢ φ → S ∈ Clsd ⁡ J
Assertion lmcld ⊢ φ → P ∈ S

Proof

Step Hyp Ref Expression
1 lmff.1 ⊢ Z = ℤ ≥ M
2 lmff.3 ⊢ φ → J ∈ TopOn ⁡ X
3 lmff.4 ⊢ φ → M ∈ ℤ
4 lmcls.5 ⊢ φ → F ⇝t ⁡ J P
5 lmcls.7 ⊢ φ ∧ k ∈ Z → F ⁡ k ∈ S
6 lmcld.8 ⊢ φ → S ∈ Clsd ⁡ J
7 eqid ⊢ ⋃ J = ⋃ J
8 7 cldss ⊢ S ∈ Clsd ⁡ J → S ⊆ ⋃ J
9 6 8 syl ⊢ φ → S ⊆ ⋃ J
10 toponuni ⊢ J ∈ TopOn ⁡ X → X = ⋃ J
11 2 10 syl ⊢ φ → X = ⋃ J
12 9 11 sseqtrrd ⊢ φ → S ⊆ X
13 1 2 3 4 5 12 lmcls ⊢ φ → P ∈ cls ⁡ J ⁡ S
14 cldcls ⊢ S ∈ Clsd ⁡ J → cls ⁡ J ⁡ S = S
15 6 14 syl ⊢ φ → cls ⁡ J ⁡ S = S
16 13 15 eleqtrd ⊢ φ → P ∈ S