U+21D4 "⇔" Left Right Double Arrow Unicode Character

U+21D4 "⇔" Left Right Double Arrow is a mathematical and logical symbol commonly known as the "if and only if" or logical biconditional operator, indicating that two statements are logically equivalent or mutually imply one another. It is also used in various fields such as set theory and computer science to denote a bidirectional relationship or equivalence between two elements. This character is part of the Unicode standard's Arrows block, designed to provide a clear, typographically consistent representation for formal reasoning and notation.