Something analogous to a group isomorphism, but that preserves whatever properties the given algebraic object has. E.g. for a field, we also have to preserve multiplication in addition to addition.
Other common examples include isomorphisms of vector spaces and field. But since both of those two are much simpler than groups in classification, as they are both determined by number of elements/dimension alone, see:
we tend to not talk about isomorphisms so much in those contexts.
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An isomorphism is a morphism with a two-sided inverse that is also a morphism. Two objects are isomorphic when such a map exists between them. For groups, rings, and vector spaces, a bijective structure-preserving map has a structure-preserving inverse; in other settings the inverse condition needs separate attention, as for a homeomorphism between topological spaces.
For example, is a group isomorphism from the additive integers to the additive even integers. It is bijective onto that target, satisfies , and has inverse . The two groups have the same addition pattern even though they are different sets. It is not a ring isomorphism for their inherited multiplications, since while .
Isomorphism is a concept that appears in various fields such as mathematics, computer science, and social science, and it generally refers to a kind of equivalence or similarity in structure between two entities. Here are a few specific contexts in which the term is often used: 1. **Mathematics**: In mathematics, particularly in algebra and topology, an isomorphism is a mapping between two structures that preserves the operations and relations of the structures.