Question

define normal subgroup of a group. show that the interaction of two normal subgroups of a group is again a normal subgroup.​

Answer 1

In abstract algebra, a normal 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 ∈ N for all g ∈ G and n ∈ N. The usual notation for this relation is .