Metamath Proof Explorer


Theorem impd

Description: Importation deduction. (Contributed by NM, 31-Mar-1994)

Ref Expression
Hypothesis impd.1 ( 𝜑 → ( 𝜓 → ( 𝜒𝜃 ) ) )
Assertion impd ( 𝜑 → ( ( 𝜓𝜒 ) → 𝜃 ) )

Proof

Step Hyp Ref Expression
1 impd.1 ( 𝜑 → ( 𝜓 → ( 𝜒𝜃 ) ) )
2 1 com3l ( 𝜓 → ( 𝜒 → ( 𝜑𝜃 ) ) )
3 2 imp ( ( 𝜓𝜒 ) → ( 𝜑𝜃 ) )
4 3 com12 ( 𝜑 → ( ( 𝜓𝜒 ) → 𝜃 ) )