Theorem exmidd

Description: Law of excluded middle in a context. (Contributed by Mario Carneiro, 9-Feb-2017)

	Ref	Expression
Assertion	exmidd	⊢ ( 𝜑 → ( 𝜓 ∨ ¬ 𝜓 ) )

Proof

Step	Hyp	Ref	Expression
1		exmid	⊢ ( 𝜓 ∨ ¬ 𝜓 )
2	1	a1i	⊢ ( 𝜑 → ( 𝜓 ∨ ¬ 𝜓 ) )