Theorem exbidv

Description: Formula-building rule for existential quantifier (deduction form). See also exbidh and exbid . (Contributed by NM, 26-May-1993)

	Ref	Expression
Hypothesis	albidv.1	|- ( ph -> ( ps <-> ch ) )
Assertion	exbidv	|- ( ph -> ( E. x ps <-> E. x ch ) )

Proof

Step	Hyp	Ref	Expression
1		albidv.1	|- ( ph -> ( ps <-> ch ) )
2		ax-5	|- ( ph -> A. x ph )
3	2 1	exbidh	|- ( ph -> ( E. x ps <-> E. x ch ) )