\UpdownarrowThe \Updownarrow symbol is used to represent a bidirectional arrow, indicating a relationship or connection that goes both upwards and downwards. It is often used in mathematical logic, set theory, and computer science to denote equivalence or duality between two statements or structures.
Logical equivalence between statements A and B
A \Updownarrow BElement x is in set A if and only if it is in set B
x \in A \Updownarrow x \in BDuality or equivalence between propositions P and Q
P \Updownarrow Q