Definition:Language of Propositional Logic/Alphabet/Sign/Bracket

Definition

The signs of the language of propositional logic include the brackets:

 $\ds \bullet \ \$ $\ds ($ $:$ $\ds$the left bracket sign $\ds \bullet \ \$ $\ds )$ $:$ $\ds$the right bracket sign

These are used as parenthesis signs.

Also defined as

Some sources use square brackets: $[$ and $]$ instead of the round brackets $($ and $)$. No doubt there are sources which use a different shape. The choice is arbitrary.

Some treatments of propositional logic do not specify brackets at all, having constructed the rules of formation to make them unnecessary.