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Metamath Proof Explorer

Theorem pm2.26

Description: Theorem *2.26 of WhiteheadRussell p. 104. See pm2.27 . (Contributed by NM, 3-Jan-2005) (Proof shortened by Wolf Lammen, 23-Nov-2012)

		Ref	Expression
	Assertion	pm2.26	$⊢ (\neg φ \lor ((φ \to ψ) \to ψ))$

Step	Hyp	Ref	Expression
1		pm2.27	$⊢ φ \to ((φ \to ψ) \to ψ)$
2	1	imori	$⊢ (\neg φ \lor ((φ \to ψ) \to ψ))$