Metamath Proof Explorer


Theorem impancom

Description: Mixed importation/commutation inference. (Contributed by NM, 22-Jun-2013)

Ref Expression
Hypothesis impancom.1 ( ( 𝜑𝜓 ) → ( 𝜒𝜃 ) )
Assertion impancom ( ( 𝜑𝜒 ) → ( 𝜓𝜃 ) )

Proof

Step Hyp Ref Expression
1 impancom.1 ( ( 𝜑𝜓 ) → ( 𝜒𝜃 ) )
2 1 ex ( 𝜑 → ( 𝜓 → ( 𝜒𝜃 ) ) )
3 2 com23 ( 𝜑 → ( 𝜒 → ( 𝜓𝜃 ) ) )
4 3 imp ( ( 𝜑𝜒 ) → ( 𝜓𝜃 ) )