Metamath Proof Explorer


Theorem abrexex

Description: Existence of a class abstraction of existentially restricted sets. See the comment of abrexexg . See also abrexex2 . (Contributed by NM, 16-Oct-2003) (Proof shortened by Mario Carneiro, 31-Aug-2015)

Ref Expression
Hypothesis abrexex.1
|- A e. _V
Assertion abrexex
|- { y | E. x e. A y = B } e. _V

Proof

Step Hyp Ref Expression
1 abrexex.1
 |-  A e. _V
2 abrexexg
 |-  ( A e. _V -> { y | E. x e. A y = B } e. _V )
3 1 2 ax-mp
 |-  { y | E. x e. A y = B } e. _V