Metamath Proof Explorer


Theorem ibir

Description: Inference that converts a biconditional implied by one of its arguments, into an implication. (Contributed by NM, 22-Jul-2004)

Ref Expression
Hypothesis ibir.1 ( 𝜑 → ( 𝜓𝜑 ) )
Assertion ibir ( 𝜑𝜓 )

Proof

Step Hyp Ref Expression
1 ibir.1 ( 𝜑 → ( 𝜓𝜑 ) )
2 1 bicomd ( 𝜑 → ( 𝜑𝜓 ) )
3 2 ibi ( 𝜑𝜓 )