Theorem bj-ax12wlem

Description: A lemma used to prove a weak version of the axiom of substitution ax-12 . (Temporary comment: The general statement that ax12wlem proves.) (Contributed by BJ, 20-Mar-2020)

	Ref	Expression
Hypothesis	bj-ax12wlem.1	|- ( ph -> ( ps <-> ch ) )
Assertion	bj-ax12wlem	|- ( ph -> ( ps -> A. x ( ph -> ps ) ) )

Proof

Step	Hyp	Ref	Expression
1		bj-ax12wlem.1	|- ( ph -> ( ps <-> ch ) )
2		ax-5	|- ( ch -> A. x ch )
3	1 2	bj-ax12i	|- ( ph -> ( ps -> A. x ( ph -> ps ) ) )