Linked from
The 19 pages that link to Identity element, each with the reason it gives.
GroupRelated: Every group has a neutral element for its operation.
Fundamental groupRelated: The constant loop represents the identity in the fundamental group.
Group homomorphismRelated: A group homomorphism sends the source identity to the target identity.
SubgroupRelated: Every subgroup must contain the identity of the ambient group.
Abelian groupRelated: Its existence is one of the group axioms inherited by Abelian groups.
Binary operationRelated: Some binary operations have a neutral input that preserves the other input.
Conjugacy classRelated: It forms a conjugacy class by itself in every group.
MonoidRelated: Its presence distinguishes a monoid from a general semigroup.
SemigroupRelated: A semigroup need not contain one, unlike a monoid.
Inverse elementRelated: The inverse is defined by combining to this element.
Commutative propertyRelated: An operation can have an identity element without being commutative.