Theorem ax6b 1581

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 1467	. 2 |- ( A. x ph -> A. x A. x ph )
2	1	ax6blem 1580	1 |- ( -. A. x ph -> A. x -. A. x ph )

Syntax hints:   -. wn 3   -> wi 4   A.wal 1282

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 104  ax-ia2 105  ax-ia3 106  ax-in1 576  ax-in2 577  ax-5 1376  ax-gen 1378  ax-ie2 1423  ax-ial 1467

This theorem depends on definitions:  df-bi 115  df-tru 1287  df-fal 1290

This theorem is referenced by:  hbn1  1582  hbnt  1583