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