(definition)

**Definition:**
A computation which takes some inputs and yields an output. Any particular input may yield different outputs at different times. Formally, a mapping from each element in the *domain* to one or more elements in the *range*.

**Specialization** (... is a kind of me.)

*function*, *binary relation*.

*Note:
Cosine is a function, since every angle has a specific cosine. Its inverse cos ^{-1}(x) is a relation, since a cosine value maps to many (for this relation, infinitely many) angles.*

Author: PEB

Go to the Dictionary of Algorithms and Data Structures home page.

If you have suggestions, corrections, or comments, please get in touch with Paul Black.

Entry modified 18 December 2003.

HTML page formatted Tue Feb 12 10:57:43 2019.

Cite this as:

Paul E. Black, "relation", in
*Dictionary of Algorithms and Data Structures* [online], Vreda Pieterse and Paul E. Black, eds. 18 December 2003. (accessed TODAY)
Available from: https://www.nist.gov/dads/HTML/relation.html