Rule of Distribution/Disjunction Distributes over Conjunction/Right Distributive/Formulation 1/Forward Implication

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Definition

$\paren {q \land r} \lor p \vdash \paren {q \lor p} \land \paren {r \lor p}$


Proof

By the tableau method of natural deduction:

$\paren {q \land r} \lor p \vdash \paren {q \lor p} \land \paren {r \lor p} $
Line Pool Formula Rule Depends upon Notes
1 1 $\paren {q \land r} \lor p$ Premise (None)
2 1 $p \lor \paren {q \land r}$ Sequent Introduction 1 Disjunction is Commutative
3 1 $\paren {p \lor q} \land \paren {p \lor r}$ Sequent Introduction 2 Disjunction is Left Distributive over Conjunction
4 1 $\paren {q \lor p} \land \paren {r \lor p}$ Sequent Introduction 3 Disjunction is Commutative

$\blacksquare$