Theorem norasslem2 1564

Description: This lemma specializes biimt 363 suitably for the proof of norass 1566. (Contributed by Wolf Lammen, 18-Dec-2023.)

Assertion

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

Proof of Theorem norasslem2

Step	Hyp	Ref	Expression
1		biimt 363	. 2 ⊢ ((𝜑 ∨ 𝜒) → (𝜓 ↔ ((𝜑 ∨ 𝜒) → 𝜓)))
2	1	orcs 888	1 ⊢ (𝜑 → (𝜓 ↔ ((𝜑 ∨ 𝜒) → 𝜓)))

This proof depends on syntax axioms:   → wi 4   ↔ wb 209   ∨ wo 860

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8

This proof depends on definitions:  df-bi 210  df-or 861

This theorem is used by:  norass  1566