Theorem bj-bijust0ALT

Description: Alternate proof of bijust0 ; shorter but using additional intermediate results. (Contributed by NM, 11-May-1999) (Proof shortened by Josh Purinton, 29-Dec-2000) (Revised by BJ, 19-Mar-2020) (Proof modification is discouraged.) (New usage is discouraged.)

	Ref	Expression
Assertion	bj-bijust0ALT	⊢ ¬ ( ( 𝜑 → 𝜑 ) → ¬ ( 𝜑 → 𝜑 ) )

Proof

Step	Hyp	Ref	Expression
1		id	⊢ ( 𝜑 → 𝜑 )
2	1	bj-nimni	⊢ ¬ ( ( 𝜑 → 𝜑 ) → ¬ ( 𝜑 → 𝜑 ) )