Linked from
The 9 pages that link to Inverse element, each with the reason it gives.
GroupRelated: Each group element must have a partner that reverses its effect.
Fundamental groupRelated: Reversing a loop gives the class that cancels it under concatenation.
Group homomorphismRelated: Preservation of products forces homomorphisms to preserve inverses.
SubgroupRelated: Subgroup membership requires inverses to remain in the subset.
Identity elementRelated: The identity is the target result in the definition of an inverse.
Abelian groupRelated: Every element of an Abelian group must have an inverse.