Metamath Proof Explorer


Theorem wuncss

Description: The weak universe closure is a subset of any other weak universe containing the set. (Contributed by Mario Carneiro, 2-Jan-2017)

Ref Expression
Assertion wuncss ⊢ U ∈ WUni ∧ A ⊆ U → wUniCl ⁡ A ⊆ U

Proof

Step Hyp Ref Expression
1 ssexg ⊢ A ⊆ U ∧ U ∈ WUni → A ∈ V
2 1 ancoms ⊢ U ∈ WUni ∧ A ⊆ U → A ∈ V
3 wuncval ⊢ A ∈ V → wUniCl ⁡ A = ⋂ u ∈ WUni | A ⊆ u
4 2 3 syl ⊢ U ∈ WUni ∧ A ⊆ U → wUniCl ⁡ A = ⋂ u ∈ WUni | A ⊆ u
5 sseq2 ⊢ u = U → A ⊆ u ↔ A ⊆ U
6 5 intminss ⊢ U ∈ WUni ∧ A ⊆ U → ⋂ u ∈ WUni | A ⊆ u ⊆ U
7 4 6 eqsstrd ⊢ U ∈ WUni ∧ A ⊆ U → wUniCl ⁡ A ⊆ U