Metamath Proof Explorer


Theorem eldmcoss

Description: Elementhood in the domain of cosets. (Contributed by Peter Mazsa, 29-Mar-2019)

Ref Expression
Assertion eldmcoss ⊢ A ∈ V → A ∈ dom ⁡ ≀ R ↔ ∃ u u R A

Proof

Step Hyp Ref Expression
1 dmcoss3 ⊢ dom ⁡ ≀ R = dom ⁡ R -1
2 1 eleq2i ⊢ A ∈ dom ⁡ ≀ R ↔ A ∈ dom ⁡ R -1
3 eldmcnv ⊢ A ∈ V → A ∈ dom ⁡ R -1 ↔ ∃ u u R A
4 2 3 bitrid ⊢ A ∈ V → A ∈ dom ⁡ ≀ R ↔ ∃ u u R A