Theorem dral2-o

Description: Formula-building lemma for use with the Distinctor Reduction Theorem. Part of Theorem 9.4 of Megill p. 448 (p. 16 of preprint). Version of dral2 using ax-c11 . (Contributed by NM, 27-Feb-2005) (Proof modification is discouraged.) (New usage is discouraged.)

	Ref	Expression
Hypothesis	dral2-o.1	|- ( A. x x = y -> ( ph <-> ps ) )
Assertion	dral2-o	|- ( A. x x = y -> ( A. z ph <-> A. z ps ) )

Proof

Step	Hyp	Ref	Expression
1		dral2-o.1	|- ( A. x x = y -> ( ph <-> ps ) )
2		hbae-o	|- ( A. x x = y -> A. z A. x x = y )
3	2 1	albidh	|- ( A. x x = y -> ( A. z ph <-> A. z ps ) )