Theorem con1bii2

Description: A contraposition inference. (Contributed by ML, 18-Oct-2020)

	Ref	Expression
Hypothesis	con1bii2.1	⊢ ( ¬ 𝜑 ↔ 𝜓 )
Assertion	con1bii2	⊢ ( 𝜑 ↔ ¬ 𝜓 )

Proof

Step	Hyp	Ref	Expression
1		con1bii2.1	⊢ ( ¬ 𝜑 ↔ 𝜓 )
2	1	con1bii	⊢ ( ¬ 𝜓 ↔ 𝜑 )
3	2	bicomi	⊢ ( 𝜑 ↔ ¬ 𝜓 )