User:Lord Farin/Tableau Proof Rules/Addition

Addition
Given statement $p$, we have also $p \lor q$ and $q \lor p$.


 * align="right" | $j$ ||
 * align="right" | $I$
 * $p \lor q$
 * $\lor \mathcal I_1$
 * $i$
 * align="right" | $k$ ||
 * align="right" | $I$
 * $q \lor p$
 * $\lor \mathcal I_2$
 * $i$
 * $\lor \mathcal I_2$
 * $i$