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identity function

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Also known as identity map, identity transformation, identity operator, id, identity relation

function that always returns the same value that was used as its argument

~3 min read

Encyclopedic overview

Graph of the identity function on the real numbers

In mathematics, an identity function, also called an identity relation, identity map or identity transformation, is a function that always returns the value that was used as its argument, unchanged. That is, when

Excerpted from Wikipedia’s “identity function” article, available under the CC BY-SA 4.0 licence.