Theorem notbinot2

Description: Commutation rule between negation and biconditional. (Contributed by Giovanni Mascellani, 15-Sep-2017)

	Ref	Expression
Assertion	notbinot2	⊢ ( ¬ ( 𝜑 ↔ 𝜓 ) ↔ ( ¬ 𝜑 ↔ 𝜓 ) )

Proof

Step	Hyp	Ref	Expression
1		nbbn	⊢ ( ( ¬ 𝜑 ↔ 𝜓 ) ↔ ¬ ( 𝜑 ↔ 𝜓 ) )
2	1	bicomi	⊢ ( ¬ ( 𝜑 ↔ 𝜓 ) ↔ ( ¬ 𝜑 ↔ 𝜓 ) )