Metamath Proof Explorer


Theorem impbida

Description: Deduce an equivalence from two implications. Variant of impbid . (Contributed by NM, 17-Feb-2007)

Ref Expression
Hypotheses impbida.1 ( ( 𝜑𝜓 ) → 𝜒 )
impbida.2 ( ( 𝜑𝜒 ) → 𝜓 )
Assertion impbida ( 𝜑 → ( 𝜓𝜒 ) )

Proof

Step Hyp Ref Expression
1 impbida.1 ( ( 𝜑𝜓 ) → 𝜒 )
2 impbida.2 ( ( 𝜑𝜒 ) → 𝜓 )
3 1 ex ( 𝜑 → ( 𝜓𝜒 ) )
4 2 ex ( 𝜑 → ( 𝜒𝜓 ) )
5 3 4 impbid ( 𝜑 → ( 𝜓𝜒 ) )