Metamath Proof Explorer


Theorem pm5.32da

Description: Distribution of implication over biconditional (deduction form). (Contributed by NM, 9-Dec-2006)

Ref Expression
Hypothesis pm5.32da.1 φ ψ χ θ
Assertion pm5.32da φ ψ χ ψ θ

Proof

Step Hyp Ref Expression
1 pm5.32da.1 φ ψ χ θ
2 1 ex φ ψ χ θ
3 2 pm5.32d φ ψ χ ψ θ