Theorem bj-exa1i

Description: Add an antecedent in an existentially quantified formula. Inference associated with exa1 . (Contributed by BJ, 6-Oct-2018)

	Ref	Expression
Hypothesis	bj-exa1i.1	|- E. x ph
Assertion	bj-exa1i	|- E. x ( ps -> ph )

Proof

Step	Hyp	Ref	Expression
1		bj-exa1i.1	|- E. x ph
2		exa1	|- ( E. x ph -> E. x ( ps -> ph ) )
3	1 2	ax-mp	|- E. x ( ps -> ph )