# Category:Identity Elements

This category contains results about Identity Elements in the context of Abstract Algebra.
Definitions specific to this category can be found in Definitions/Identity Elements.

An element $e \in S$ is called an identity (element) if and only if it is both a left identity and a right identity:

$\forall x \in S: x \circ e = x = e \circ x$

In Identity is Unique it is established that an identity element, if it exists, is unique within $\struct {S, \circ}$.

Thus it is justified to refer to it as the identity (of a given algebraic structure).

This identity is often denoted $e_S$, or $e$ if it is clearly understood what structure is being discussed.

## Subcategories

This category has the following 5 subcategories, out of 5 total.

## Pages in category "Identity Elements"

The following 35 pages are in this category, out of 35 total.