Metamath Proof Explorer


Theorem pm2.62

Description: Theorem *2.62 of WhiteheadRussell p. 107. (Contributed by NM, 3-Jan-2005) (Proof shortened by Wolf Lammen, 13-Dec-2013)

Ref Expression
Assertion pm2.62 ( ( 𝜑𝜓 ) → ( ( 𝜑𝜓 ) → 𝜓 ) )

Proof

Step Hyp Ref Expression
1 pm2.621 ( ( 𝜑𝜓 ) → ( ( 𝜑𝜓 ) → 𝜓 ) )
2 1 com12 ( ( 𝜑𝜓 ) → ( ( 𝜑𝜓 ) → 𝜓 ) )