Symmetric relations

In mathematics, a relation \( R \) on a set \( A \) is called symmetric if, for any elements \( a \) and \( b \) in \( A \), whenever \( a \) is related to \( b \) (i.e., \( (a, b) \in R \)), it also holds that \( b \) is related to \( a \) (i.e., \( (b, a) \in R \)).