Theorem atbiffatnnbalt

Description: If a implies b, then a implies not not b. (Contributed by Jarvin Udandy, 29-Aug-2016)

	Ref	Expression
Assertion	atbiffatnnbalt	⊢ ( ( 𝜑 → 𝜓 ) → ( 𝜑 → ¬ ¬ 𝜓 ) )

Proof

Step	Hyp	Ref	Expression
1		atbiffatnnb	⊢ ( ( 𝜑 → 𝜓 ) → ( 𝜑 → ¬ ¬ 𝜓 ) )