Theorem pm2.07

Description: Theorem *2.07 of WhiteheadRussell p. 101. (Contributed by NM, 3-Jan-2005)

	Ref	Expression
Assertion	pm2.07	$$⊢\phi \to \left(\phi \vee \phi \right)$$

Proof

Step	Hyp	Ref	Expression
1		olc	$$⊢\phi \to \left(\phi \vee \phi \right)$$