Metamath Proof Explorer


Theorem dm1cosscnvepres

Description: The domain of cosets of the restricted converse epsilon relation is the union of the restriction. (Contributed by Peter Mazsa, 18-May-2019) (Revised by Peter Mazsa, 26-Sep-2021)

Ref Expression
Assertion dm1cosscnvepres ⊢ dom ⁡ ≀ E -1 ↾ A = ⋃ A

Proof

Step Hyp Ref Expression
1 dmcoss2 ⊢ dom ⁡ ≀ E -1 ↾ A = ran ⁡ E -1 ↾ A
2 rncnvepres ⊢ ran ⁡ E -1 ↾ A = ⋃ A
3 1 2 eqtri ⊢ dom ⁡ ≀ E -1 ↾ A = ⋃ A