(

Punctuation mark

 * 1) Represents a mouth vertically aligned, in order to form emoticons.

Symbol

 * $$(a,b]=\{x\in\R\,|\,a<x\le b\}$$
 * $$(a,b]=\{x\in\R\,|\,a<x\le b\}$$

Punctuation mark

 * 1) Used in.