Metamath Proof Explorer


Theorem pm2.43d

Description: Deduction absorbing redundant antecedent. Deduction associated with pm2.43 and pm2.43i . (Contributed by NM, 18-Aug-1993) (Proof shortened by Mel L. O'Cat, 28-Nov-2008)

Ref Expression
Hypothesis pm2.43d.1
|- ( ph -> ( ps -> ( ps -> ch ) ) )
Assertion pm2.43d
|- ( ph -> ( ps -> ch ) )

Proof

Step Hyp Ref Expression
1 pm2.43d.1
 |-  ( ph -> ( ps -> ( ps -> ch ) ) )
2 id
 |-  ( ps -> ps )
3 2 1 mpdi
 |-  ( ph -> ( ps -> ch ) )