Metamath Proof Explorer


Theorem qsexg

Description: A quotient set exists. (Contributed by FL, 19-May-2007) (Revised by Mario Carneiro, 9-Jul-2014)

Ref Expression
Assertion qsexg A V A / R V

Proof

Step Hyp Ref Expression
1 df-qs A / R = y | x A y = x R
2 abrexexg A V y | x A y = x R V
3 1 2 eqeltrid A V A / R V