Definition:Isomorphism


 * Isomorphism (Abstract Algebra): An isomorphism between two algebraic structures is a bijection which preserves operations.
 * Group isomorphism: an isomorphism between two groups.
 * Ring isomorphism: an isomorphism between two rings.
 * R-algebraic structure isomorphism: an isomorphism between two R-algebraic structures.


 * Isomorphism (Graph Theory): An isomorphism between two graphs is a bijection which preserves incidences between edges and vertices.


 * Relation isomorphism: A isomorphism between two relational structures is a bijection which preserves relations.


 * Order isomorphism: An (order) isomorphism between two posets is a bijection which preserves ordering.


 * Isomorphism (Topology): still to be defined.