Metamath Proof Explorer


Theorem pm2.07

Description: Theorem *2.07 of WhiteheadRussell p. 101. (Contributed by NM, 3-Jan-2005)

Ref Expression
Assertion pm2.07 ( 𝜑 → ( 𝜑𝜑 ) )

Proof

Step Hyp Ref Expression
1 olc ( 𝜑 → ( 𝜑𝜑 ) )