Metamath Proof Explorer


Theorem bitr2di

Description: A syllogism inference from two biconditionals. (Contributed by NM, 5-Aug-1993)

Ref Expression
Hypotheses bitr2di.1 ( 𝜑 → ( 𝜓𝜒 ) )
bitr2di.2 ( 𝜒𝜃 )
Assertion bitr2di ( 𝜑 → ( 𝜃𝜓 ) )

Proof

Step Hyp Ref Expression
1 bitr2di.1 ( 𝜑 → ( 𝜓𝜒 ) )
2 bitr2di.2 ( 𝜒𝜃 )
3 1 2 bitrdi ( 𝜑 → ( 𝜓𝜃 ) )
4 3 bicomd ( 𝜑 → ( 𝜃𝜓 ) )