Metamath Proof Explorer


Theorem hbnd

Description: Deduction form of bound-variable hypothesis builder hbn . (Contributed by NM, 3-Jan-2002)

Ref Expression
Hypotheses hbnd.1
|- ( ph -> A. x ph )
hbnd.2
|- ( ph -> ( ps -> A. x ps ) )
Assertion hbnd
|- ( ph -> ( -. ps -> A. x -. ps ) )

Proof

Step Hyp Ref Expression
1 hbnd.1
 |-  ( ph -> A. x ph )
2 hbnd.2
 |-  ( ph -> ( ps -> A. x ps ) )
3 1 2 alrimih
 |-  ( ph -> A. x ( ps -> A. x ps ) )
4 hbnt
 |-  ( A. x ( ps -> A. x ps ) -> ( -. ps -> A. x -. ps ) )
5 3 4 syl
 |-  ( ph -> ( -. ps -> A. x -. ps ) )