\begin{definition}[Definition:Language of Propositional Logic/Labeled Tree]
There are many formal languages expressing propositional logic.
The formal language used on {{ProofWiki}} is defined on Definition:Language of Propositional Logic.
This page defines the formal language $\LL_0$ used in:
* {{BookReference|Mathematical Logic for Computer Science|2012|M. Ben-Ari|ed=3rd|edpage=Third Edition}}
Explanations are omitted as this is intended for reference use only.
\end{definition}