Group homomorphisms and kernels
Homomorphisms preserve the group operation.
Key knowledge
A group homomorphism φ:G→H satisfies φ(ab)=φ(a)φ(b). It preserves identity and inverses. Its kernel, the elements mapped to H's identity, is a normal subgroup of G.
Values and equations
φ(ab) = φ(a)φ(b); ker φ = {g ∈ G : φ(g)=e_H}
- φ
- Group homomorphism
- G, H
- Domain and codomain groups
- e_H
- Identity in H
Conditions and scope
- The two products are the respective group operations.
- A homomorphism need not be injective or surjective.
Sources · 1
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Operation-preserving definition, Proposition 4.16 and kernel Theorem 4.17.
2026-10-10 · Operation preservation and kernel normality.
Entry details
Permanent link to this entry ↗- Record identity
- math-group-homomorphisms
- Revision
- university-reference.1
- Structured reference record
- University reference