Rule of Commutation/Disjunction/Formulation 1/Proof 1

Theorem

 * $p \lor q \dashv \vdash q \lor p$

Proof

 * align="right" | 6 ||
 * align="right" | 1
 * $q \lor p$
 * $\lor \mathcal E$
 * 1, 2-3, 4-5
 * 1, 2-3, 4-5


 * align="right" | 6 ||
 * align="right" | 1
 * $p \lor q$
 * $\lor \mathcal E$
 * 1, 2-3, 4-5
 * 1, 2-3, 4-5