Metamath Proof Explorer


Theorem ifpbi23

Description: Equivalence theorem for conditional logical operators. (Contributed by RP, 15-Apr-2020)

Ref Expression
Assertion ifpbi23 φ ψ χ θ if- τ φ χ if- τ ψ θ

Proof

Step Hyp Ref Expression
1 simpl φ ψ χ θ φ ψ
2 simpr φ ψ χ θ χ θ
3 1 2 ifpbi23d φ ψ χ θ if- τ φ χ if- τ ψ θ