Metamath Proof Explorer


Theorem bi3impb

Description: Similar to 3impb with implication in hypothesis replaced by biconditional. (Contributed by Alan Sare, 6-Nov-2017)

Ref Expression
Hypothesis bi3impb.1 φ ψ χ θ
Assertion bi3impb φ ψ χ θ

Proof

Step Hyp Ref Expression
1 bi3impb.1 φ ψ χ θ
2 1 biimpi φ ψ χ θ
3 2 3impb φ ψ χ θ