Metamath Proof Explorer


Theorem pm5.44

Description: Theorem *5.44 of WhiteheadRussell p. 125. (Contributed by NM, 3-Jan-2005)

Ref Expression
Assertion pm5.44 ( ( 𝜑𝜓 ) → ( ( 𝜑𝜒 ) ↔ ( 𝜑 → ( 𝜓𝜒 ) ) ) )

Proof

Step Hyp Ref Expression
1 jcab ( ( 𝜑 → ( 𝜓𝜒 ) ) ↔ ( ( 𝜑𝜓 ) ∧ ( 𝜑𝜒 ) ) )
2 1 baibr ( ( 𝜑𝜓 ) → ( ( 𝜑𝜒 ) ↔ ( 𝜑 → ( 𝜓𝜒 ) ) ) )