Theorem reximdvaiOLD

Description: Obsolete version of reximdvai as of 3-Nov-2024. (Contributed by NM, 14-Nov-2002) Reduce dependencies on axioms. (Revised by Wolf Lammen, 8-Jan-2020) (Proof modification is discouraged.) (New usage is discouraged.)

	Ref	Expression
Hypothesis	reximdvai.1	|- ( ph -> ( x e. A -> ( ps -> ch ) ) )
Assertion	reximdvaiOLD	|- ( ph -> ( E. x e. A ps -> E. x e. A ch ) )

Proof

Step	Hyp	Ref	Expression
1		reximdvai.1	|- ( ph -> ( x e. A -> ( ps -> ch ) ) )
2	1	ralrimiv	|- ( ph -> A. x e. A ( ps -> ch ) )
3		rexim	|- ( A. x e. A ( ps -> ch ) -> ( E. x e. A ps -> E. x e. A ch ) )
4	2 3	syl	|- ( ph -> ( E. x e. A ps -> E. x e. A ch ) )