Metamath Proof Explorer


Theorem baibd

Description: Move conjunction outside of biconditional. (Contributed by Mario Carneiro, 11-Sep-2015)

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

Proof

Step Hyp Ref Expression
1 baibd.1 φ ψ χ θ
2 ibar χ θ χ θ
3 2 bicomd χ χ θ θ
4 1 3 sylan9bb φ χ ψ θ