Metamath Proof Explorer

Theorem bnj1239

Description: First-order logic and set theory. (Contributed by Jonathan Ben-Naim, 3-Jun-2011) (New usage is discouraged.)

Ref Expression
Assertion bnj1239 
|- ( E. x e. A ( ps /\ ch ) -> E. x e. A ps )

Proof

Step Hyp Ref Expression
1 simpl 
 |-  ( ( ps /\ ch ) -> ps )
2 1 reximi 
 |-  ( E. x e. A ( ps /\ ch ) -> E. x e. A ps )