Metamath Proof Explorer


Theorem pm3.45

Description: Theorem *3.45 (Fact) of WhiteheadRussell p. 113. (Contributed by NM, 3-Jan-2005)

Ref Expression
Assertion pm3.45 ( ( 𝜑𝜓 ) → ( ( 𝜑𝜒 ) → ( 𝜓𝜒 ) ) )

Proof

Step Hyp Ref Expression
1 id ( ( 𝜑𝜓 ) → ( 𝜑𝜓 ) )
2 1 anim1d ( ( 𝜑𝜓 ) → ( ( 𝜑𝜒 ) → ( 𝜓𝜒 ) ) )