retract
/ɹɪˈtɹækt/
verb13
noun5
- A subgroup of a given group such that there is a surjective endomorphism from the ambient group to the subgroup which is constant on the subgroup; in this case the subgroup is a retract of the ambient group. In symbols: H in G is a retract of G if there exists a surjective homomorphism σ from G to H with σ|_H= operatorname id.
forms
retracted · retracting · retracteth · retracts · retractest