Theorem pm2.41 907

Description: Theorem *2.41 of [WhiteheadRussell] p. 106. (Contributed by NM, 3-Jan-2005.)

Assertion

Ref	Expression
pm2.41	⊢ ((𝜓 ∨ (𝜑 ∨ 𝜓)) → (𝜑 ∨ 𝜓))

Proof of Theorem pm2.41

Step	Hyp	Ref	Expression
1		olc 868	. 2 ⊢ (𝜓 → (𝜑 ∨ 𝜓))
2		id 22	. 2 ⊢ ((𝜑 ∨ 𝜓) → (𝜑 ∨ 𝜓))
3	1, 2	jaoi 857	1 ⊢ ((𝜓 ∨ (𝜑 ∨ 𝜓)) → (𝜑 ∨ 𝜓))

Syntax hints:   → wi 4   ∨ wo 847

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8

This theorem depends on definitions:  df-bi 207  df-or 848

This theorem is referenced by: (None)