Theorem pm2.24 101

Description: Theorem *2.24 of [WhiteheadRussell] p. 104. (Contributed by NM, 3-Jan-2005.)

Assertion

Ref	Expression
pm2.24	⊢ (φ → (¬ φ → ψ))

Proof of Theorem pm2.24

Step	Hyp	Ref	Expression
1		pm2.21 100	. 2 ⊢ (¬ φ → (φ → ψ))
2	1	com12 27	1 ⊢ (φ → (¬ φ → ψ))

Syntax hints:  ¬ wn 3   → wi 4

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

This theorem is referenced by:  pm4.81  355  orc  374  pm2.82  825  dedlema  920