Theorem ax6b 1665

Description: Quantified Negation. Axiom C5-2 of [Monk2] p. 113.

(Contributed by GD, 27-Jan-2018.)

Assertion

Ref	Expression
ax6b	|- ( -. A. x ph -> A. x -. A. x ph )

Proof of Theorem ax6b

Step	Hyp	Ref	Expression
1		ax-ial 1548	. 2 |- ( A. x ph -> A. x A. x ph )
2	1	ax6blem 1664	1 |- ( -. A. x ph -> A. x -. A. x ph )

Syntax hints:   -. wn 3   -> wi 4   A.wal 1362

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-in1 615  ax-in2 616  ax-5 1461  ax-gen 1463  ax-ie2 1508  ax-ial 1548

This theorem depends on definitions:  df-bi 117  df-tru 1367  df-fal 1370

This theorem is referenced by:  hbn1  1666  hbnt  1667