Tautological Antecedent/Proof 1
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Theorem
- $\top \implies p \dashv \vdash p$
Proof
By the tableau method of natural deduction:
Line | Pool | Formula | Rule | Depends upon | Notes | |
---|---|---|---|---|---|---|
1 | 1 | $\top \implies p$ | Premise | (None) | ||
2 | $\top$ | Rule of Top-Introduction: $\top \II$ | (None) | |||
3 | 1 | $p$ | Modus Ponendo Ponens: $\implies \mathcal E$ | 1, 2 |
$\Box$
By the tableau method of natural deduction:
Line | Pool | Formula | Rule | Depends upon | Notes | |
---|---|---|---|---|---|---|
1 | 1 | $p$ | Premise | (None) | ||
2 | 2 | $\top$ | Assumption | (None) | ||
3 | 1 | $\top \implies p$ | Rule of Implication: $\implies \II$ | 2 – 1 | Assumption 2 has been discharged |
$\blacksquare$