Metamath Proof Explorer


Theorem dfifp7

Description: Alternate definition of the conditional operator for propositions. (Contributed by BJ, 2-Oct-2019)

Ref Expression
Assertion dfifp7 if- φ ψ χ χ φ φ ψ

Proof

Step Hyp Ref Expression
1 orcom φ ψ ¬ χ φ ¬ χ φ φ ψ
2 dfifp6 if- φ ψ χ φ ψ ¬ χ φ
3 imor χ φ φ ψ ¬ χ φ φ ψ
4 1 2 3 3bitr4i if- φ ψ χ χ φ φ ψ