Theorem bj-fal

Description: Shortening of fal using bj-mt2bi . (Contributed by Anthony Hart, 22-Oct-2010) (Proof shortened by Mel L. O'Cat, 11-Mar-2012) (Proof modification is discouraged.)

	Ref	Expression
Assertion	bj-fal	$$⊢\neg \perp$$

Proof

Step	Hyp	Ref	Expression
1		tru	$$⊢\top$$
2		df-fal	$$⊢\perp \leftrightarrow \neg \top$$
3	1 2	bj-mt2bi	$$⊢\neg \perp$$