⟺
Symbol  Format  Data 

⟺  Code Point 
U+27FA 
TeX 
\iff 

SVG 
The ifandonlyif symbol is used as a logical statement in math. Typically the symbol is used in an expression like:
In plain language, this means that if is true, then must be true and if is false, then must be false.
Long left right arrow symbol.
Long left double arrow symbol.
The implies symbol is used in math to represent a logical implication. It signifies that if the first statement is true, then the second statement must also be true.