Theorem pm5.11g

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

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

Proof

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