Theorem 19.21bi

Description: Inference form of 19.21 and also deduction form of sp . (Contributed by NM, 26-May-1993)

	Ref	Expression
Hypothesis	19.21bi.1	|- ( ph -> A. x ps )
Assertion	19.21bi	|- ( ph -> ps )

Proof

Step	Hyp	Ref	Expression
1		19.21bi.1	|- ( ph -> A. x ps )
2		sp	|- ( A. x ps -> ps )
3	1 2	syl	|- ( ph -> ps )