This is an inofficial mirror of http://metamath.tirix.org for personal testing of a visualizer extension only.

Metamath Proof Explorer

Theorem pm2.24

Description: Theorem *2.24 of WhiteheadRussell p. 104. Its associated inference is pm2.24i . Commuted form of pm2.21 . (Contributed by NM, 3-Jan-2005)

		Ref	Expression
	Assertion	pm2.24	$⊢ φ \to (\neg φ \to ψ)$

Proof

Step	Hyp	Ref	Expression
1		pm2.21	$⊢ \neg φ \to (φ \to ψ)$
2	1	com12	$⊢ φ \to (\neg φ \to ψ)$