Theorem pm5.11g 941

Description: A general instance of Theorem *5.11 of [WhiteheadRussell] p. 123. (Contributed by NM, 3-Jan-2005.)

Assertion

Ref	Expression
pm5.11g	⊢ ((𝜑 → 𝜓) ∨ (¬ 𝜑 → 𝜒))

Proof of Theorem pm5.11g

Step	Hyp	Ref	Expression
1		pm2.5g 168	. 2 ⊢ (¬ (𝜑 → 𝜓) → (¬ 𝜑 → 𝜒))
2	1	orri 859	1 ⊢ ((𝜑 → 𝜓) ∨ (¬ 𝜑 → 𝜒))

Syntax hints:  ¬ wn 3   → wi 4   ∨ wo 844

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 206  df-or 845

This theorem is referenced by:  pm5.11  942