\nLeftrightarrowThe \nLeftrightarrow symbol is used to denote logical equivalence or a biconditional relationship between two statements. It is often used in mathematical logic and proofs to indicate that two statements are true under the same conditions.
Logical equivalence between statements A and B
A \nLeftrightarrow BBiconditional relationship between predicates P and Q
P(x) \nLeftrightarrow Q(x)Equivalence showing that x equals 2 if and only if x squared equals 4
x = 2 \nLeftrightarrow x^2 = 4