Metamath Proof Explorer


Theorem ssralvOLD

Description: Obsolete version of ssralv as of 19-May-2025. (Contributed by NM, 11-Mar-2006) (Proof modification is discouraged.) (New usage is discouraged.)

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

Proof

Step Hyp Ref Expression
1 ssel
 |-  ( A C_ B -> ( x e. A -> x e. B ) )
2 1 imim1d
 |-  ( A C_ B -> ( ( x e. B -> ph ) -> ( x e. A -> ph ) ) )
3 2 ralimdv2
 |-  ( A C_ B -> ( A. x e. B ph -> A. x e. A ph ) )