(linear algebra) A diagonal matrix all of the diagonal elements of which are equal to 1.

(algebra) An element of an algebraic structure, generally denoted 0, which is an identity for an additive operation (generally denoted +). That is, x + 0 = 0 + x = x for any x in the structure.

(algebra) An element of a structure that produces an identity mapping when applied on the right.

(algebra) An element of a structure that produces an identity mapping when applied on the left.

(algebra) An element of an algebraic structure which when applied, in either order, to any other element via a binary operation yields the other element.

(mathematics) A function whose value is always the same as its independent variable, and for which the codomain equals the domain.

(complex analysis) The equation e^(i𝜋)=-1,!, which unifies diverse fields of mathematics.

plural of e-identity

One's identity on an electronic or digital system such as the Internet.

plural of identity matrix