Metamath Proof Explorer


Theorem pm5.32rd

Description: Distribution of implication over biconditional (deduction form). (Contributed by NM, 25-Dec-2004)

Ref Expression
Hypothesis pm5.32d.1 φψχθ
Assertion pm5.32rd φχψθψ

Proof

Step Hyp Ref Expression
1 pm5.32d.1 φψχθ
2 1 pm5.32d φψχψθ
3 ancom χψψχ
4 ancom θψψθ
5 2 3 4 3bitr4g φχψθψ