In abstract algebra, a normal subgroup is a subgroup which is invariant under conjugation by members of the group of which it is a part. In other words, a subgroup H of a group G is normal in G if and only if aH = Ha for all a in G (see coset). Normal subgroups (and only normal subgroups) can be used to construct quotient groups from a given group.
Évariste Galois was the first to realize the importance of the existence of normal subgroups.
Read more about Normal Subgroup: Definitions, Examples, Properties, Normal Subgroups and Homomorphisms
Famous quotes containing the word normal:
“A normal adolescent is so restless and twitchy and awkward that he can mange to injure his knee—not playing soccer, not playing football—but by falling off his chair in the middle of French class.”
—Judith Viorst (20th century)