Theorem bj-falor

Description: Dual of truan (which has biconditional reversed). (Contributed by BJ, 26-Oct-2019) (Proof modification is discouraged.)

	Ref	Expression
Assertion	bj-falor	$$⊢\phi \leftrightarrow \left(\perp \vee \phi \right)$$

Proof

Step	Hyp	Ref	Expression
1		fal	$$⊢\neg \perp$$
2	1	biorfi	$$⊢\phi \leftrightarrow \left(\perp \vee \phi \right)$$