Metamath Proof Explorer


Theorem dfifp6

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

Ref Expression
Assertion dfifp6 if- φ ψ χ φ ψ ¬ χ φ

Proof

Step Hyp Ref Expression
1 df-ifp if- φ ψ χ φ ψ ¬ φ χ
2 ancom ¬ φ χ χ ¬ φ
3 annim χ ¬ φ ¬ χ φ
4 2 3 bitri ¬ φ χ ¬ χ φ
5 4 orbi2i φ ψ ¬ φ χ φ ψ ¬ χ φ
6 1 5 bitri if- φ ψ χ φ ψ ¬ χ φ