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Theorem pm2.43d 44
Description: Deduction absorbing redundant antecedent. (Contributed by NM, 18-Aug-1993.) (Proof shortened by O'Cat, 28-Nov-2008.)
Hypothesis
Ref Expression
pm2.43d.1 (φ → (ψ → (ψχ)))
Assertion
Ref Expression
pm2.43d (φ → (ψχ))

Proof of Theorem pm2.43d
StepHypRef Expression
1 id 19 . 2 (ψψ)
2 pm2.43d.1 . 2 (φ → (ψ → (ψχ)))
31, 2mpdi 38 1 (φ → (ψχ))
Colors of variables: wff setvar class
Syntax hints:  wi 4
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7
This theorem is referenced by:  loolinALT  95  ax12  1935  ax10lem4  1941  ax12from12o  2156  rgen2a  2680  rspct  2948  ncfinraise  4481  funssres  5144  2elresin  5194
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