Metamath Proof Explorer


Theorem exp4c

Description: An exportation inference. (Contributed by NM, 26-Apr-1994)

Ref Expression
Hypothesis exp4c.1 ( 𝜑 → ( ( ( 𝜓𝜒 ) ∧ 𝜃 ) → 𝜏 ) )
Assertion exp4c ( 𝜑 → ( 𝜓 → ( 𝜒 → ( 𝜃𝜏 ) ) ) )

Proof

Step Hyp Ref Expression
1 exp4c.1 ( 𝜑 → ( ( ( 𝜓𝜒 ) ∧ 𝜃 ) → 𝜏 ) )
2 1 expd ( 𝜑 → ( ( 𝜓𝜒 ) → ( 𝜃𝜏 ) ) )
3 2 expd ( 𝜑 → ( 𝜓 → ( 𝜒 → ( 𝜃𝜏 ) ) ) )