Normal subgroup
SUBGROUP INVARIANT UNDER CONJUGATION
Normal subgroups; Invariant subgroup; ◅; Normal group; ⊲; ⊳; ⊴; ⊵; ⋪; ⋫; ⋬; ⋭; Normal Subgroup; Self-conjugate subgroup
In abstract algebra, a normal subgroup (also known as an invariant subgroup or self-conjugate subgroup) is a subgroup that is invariant under conjugation by members of the group of which it is a part. In other words, a subgroup N of the group G is normal in G if and only if gng^{-1} \in N for all g \in G and n \in N.