Editing Disjunction elimination (section)

== Formal notation ==
The ''disjunction elimination'' rule may be written in [[sequent]] notation:

: <math>(P \to Q), (R \to Q), (P \lor R) \vdash Q</math>

where <math>\vdash</math> is a [[metalogic]]al symbol meaning that <math>Q</math> is a [[logical consequence|syntactic consequence]] of <math>P \to Q</math>, and <math>R \to Q</math> and <math>P \lor R</math> in some logical system;

and expressed as a truth-functional [[tautology (logic)|tautology]] or theorem of propositional logic:

:<math>(((P \to Q) \land (R \to Q)) \land (P \lor R)) \to Q</math>

where <math>P</math>, <math>Q</math>, and <math>R</math> are propositions expressed in some [[formal system]].