Theorem pm2.48 897

Description: Theorem *2.48 of [WhiteheadRussell] p. 107. (Contributed by NM, 3-Jan-2005.)

Assertion

Ref	Expression
pm2.48	⊢ (¬ (𝜑 ∨ 𝜓) → (𝜑 ∨ ¬ 𝜓))

Proof of Theorem pm2.48

Step	Hyp	Ref	Expression
1		pm2.46 895	. 2 ⊢ (¬ (𝜑 ∨ 𝜓) → ¬ 𝜓)
2	1	olcd 887	1 ⊢ (¬ (𝜑 ∨ 𝜓) → (𝜑 ∨ ¬ 𝜓))

This proof depends on syntax axioms:  ¬ wn 3   → wi 4   ∨ 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: (None)