Theorem pm2.26 853

Description: Theorem *2.26 of [WhiteheadRussell] p. 104. (Contributed by NM, 3-Jan-2005.) (Proof shortened by Wolf Lammen, 23-Nov-2012.)

Assertion

Ref	Expression
pm2.26	⊢ (¬ φ ∨ ((φ → ψ) → ψ))

Proof of Theorem pm2.26

Step	Hyp	Ref	Expression
1		pm2.27 35	. 2 ⊢ (φ → ((φ → ψ) → ψ))
2	1	imori 402	1 ⊢ (¬ φ ∨ ((φ → ψ) → ψ))

Syntax hints:  ¬ wn 3   → wi 4   ∨ wo 357

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 177  df-or 359

This theorem is referenced by: (None)