Theorem reximdv

Description: Deduction from Theorem 19.22 of Margaris p. 90. (Restricted quantifier version with strong hypothesis.) (Contributed by NM, 24-Jun-1998)

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

Proof

Step	Hyp	Ref	Expression
1		reximdv.1	|- ( ph -> ( ps -> ch ) )
2	1	a1d	|- ( ph -> ( x e. A -> ( ps -> ch ) ) )
3	2	reximdvai	|- ( ph -> ( E. x e. A ps -> E. x e. A ch ) )