Metamath Proof Explorer


Theorem disjdmqs

Description: If a relation is disjoint, its domain quotient is equal to the domain quotient of the cosets by it. Lemma for partim2 and petlem via disjdmqseq . (Contributed by Peter Mazsa, 16-Sep-2021)

Ref Expression
Assertion disjdmqs Disj R dom R / R = dom R / R

Proof

Step Hyp Ref Expression
1 disjdmqsss Disj R dom R / R dom R / R
2 disjdmqscossss Disj R dom R / R dom R / R
3 1 2 eqssd Disj R dom R / R = dom R / R