Theorem norasslem2

Description: This lemma specializes biimt suitably for the proof of norass . (Contributed by Wolf Lammen, 18-Dec-2023)

	Ref	Expression
Assertion	norasslem2	⊢ ( 𝜑 → ( 𝜓 ↔ ( ( 𝜑 ∨ 𝜒 ) → 𝜓 ) ) )

Proof

Step	Hyp	Ref	Expression
1		orc	⊢ ( 𝜑 → ( 𝜑 ∨ 𝜒 ) )
2		biimt	⊢ ( ( 𝜑 ∨ 𝜒 ) → ( 𝜓 ↔ ( ( 𝜑 ∨ 𝜒 ) → 𝜓 ) ) )
3	1 2	syl	⊢ ( 𝜑 → ( 𝜓 ↔ ( ( 𝜑 ∨ 𝜒 ) → 𝜓 ) ) )