Metamath Proof Explorer


Theorem biimparc

Description: Importation inference from a logical equivalence. (Contributed by NM, 3-May-1994)

Ref Expression
Hypothesis biimpa.1 ( 𝜑 → ( 𝜓𝜒 ) )
Assertion biimparc ( ( 𝜒𝜑 ) → 𝜓 )

Proof

Step Hyp Ref Expression
1 biimpa.1 ( 𝜑 → ( 𝜓𝜒 ) )
2 1 biimprcd ( 𝜒 → ( 𝜑𝜓 ) )
3 2 imp ( ( 𝜒𝜑 ) → 𝜓 )