Citizendium - a community developing a quality, comprehensive compendium of knowledge, online and free.Click here to join and contribute |

CZ thanks our previous donors. Donate here. Treasurer's Financial Report |

# Identity (mathematics)

From Citizendium

*This disambiguation page lists articles associated with the same or a similar title.*

In mathematics, **identity** may refer to:

- Identity element, or neutral element, with respect to a binary operation, an element which leaves the other operand unchanged.
- The identity matrix, the neutral element for matrix multiplication.

- Identity function on a set to itself which maps each element to itself.
- The identity relation (mathematics) is the relation expressing equality.
- Any equality between variables which is universally true, as opposed to an equation to be solved.