Metamath Proof Explorer

Theorem hbn1

Description: Alias for ax-10 to be used instead of it. (Contributed by NM, 24-Jan-1993) (Proof shortened by Wolf Lammen, 18-Aug-2014)

Ref Expression
Assertion hbn1 
|- ( -. A. x ph -> A. x -. A. x ph )

Proof

Step Hyp Ref Expression
1 ax-10 
 |-  ( -. A. x ph -> A. x -. A. x ph )