Metamath Proof Explorer


Theorem ssrexvOLD

Description: Obsolete version of ssrexv as of 19-May-2025. (Contributed by NM, 11-Jan-2007) (Proof modification is discouraged.) (New usage is discouraged.)

Ref Expression
Assertion ssrexvOLD
|- ( A C_ B -> ( E. x e. A ph -> E. x e. B ph ) )

Proof

Step Hyp Ref Expression
1 ssel
 |-  ( A C_ B -> ( x e. A -> x e. B ) )
2 1 anim1d
 |-  ( A C_ B -> ( ( x e. A /\ ph ) -> ( x e. B /\ ph ) ) )
3 2 reximdv2
 |-  ( A C_ B -> ( E. x e. A ph -> E. x e. B ph ) )