A double-headed arrow symbol representing logical equivalence or bidirectional implications in mathematical logic and proofs.
Examples
Logical equivalence between statements
P \Lrarr Q \text{ means P if and only if Q}
Bijective function notation
f: X \Lrarr Y \text{ denotes a bijective mapping}
Mathematical equivalence
x^2 = 4 \Lrarr x = \pm 2