The maps to symbol, ↦, is a rightward arrow protruding from a vertical bar. It is used in mathematics and in computer science^[1] to denote functions.

• In Z notation, a specification language used in software development,^[2] this symbol is called the maplet arrow and the expression x ↦ y is called a maplet.
• In separation logic it denotes the contents of a specific cell of memory.

In the Unicode character set, the symbol is code point U+21A6.^[3]

The "Maps to" operator is useful when it is desirable to avoid assigning names to functions.

This can avoid possible misinterpretations due to poor naming conventions,^[4] such as avoiding the following name conflict from these two functions existing in the same file or in the same mathematical proof:

• func sqr: ${\displaystyle x\mapsto x*x}$
  • Squares the input value
• func sqr: ${\displaystyle x\mapsto (2*x)+(2*x)}$.
  • Calculates the perimeter of a square when given an input side length.

• Arrow notation – e.g., ${\displaystyle x\mapsto x+1}$, also known as map

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