Editing Bijection (section)

==Category theory==
Bijections are precisely the [[isomorphism]]s in the [[category theory|category]] ''[[Category of sets|Set]]'' of [[Set (mathematics)|sets]] and set functions.  However, the bijections are not always the isomorphisms for more complex categories.  For example, in the category ''[[Category of groups|Grp]]'' of [[Group (mathematics)|groups]], the morphisms must be [[homomorphism]]s since they must preserve the group structure, so the isomorphisms are ''group isomorphisms'' which are bijective homomorphisms.