Theorem bj-19.23bit

Description: Closed form of 19.23bi . (Contributed by BJ, 20-Oct-2019)

	Ref	Expression
Assertion	bj-19.23bit	⊢ ( ( ∃ 𝑥 𝜑 → 𝜓 ) → ( 𝜑 → 𝜓 ) )

Proof

Step	Hyp	Ref	Expression
1		19.8a	⊢ ( 𝜑 → ∃ 𝑥 𝜑 )
2	1	imim1i	⊢ ( ( ∃ 𝑥 𝜑 → 𝜓 ) → ( 𝜑 → 𝜓 ) )