# Rule of Conjunction/Sequent Form/Formulation 1/Proof 1

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## Theorem

- $p, q \vdash p \land q$

## Proof

By the tableau method of natural deduction:

Line | Pool | Formula | Rule | Depends upon | Notes | |
---|---|---|---|---|---|---|

1 | 1 | $p$ | Premise | (None) | ||

2 | 2 | $q$ | Premise | (None) | ||

3 | 1, 2 | $p \land q$ | Rule of Conjunction: $\land \mathcal I$ | 1, 2 |

$\blacksquare$

## Sources

- 1965: E.J. Lemmon:
*Beginning Logic*... (previous) ... (next): $\S 1.3$: Conjunction and Disjunction: Theorem $12$