Metamath Proof Explorer


Theorem pm5.32d

Description: Distribution of implication over biconditional (deduction form). (Contributed by NM, 29-Oct-1996)

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

Proof

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