Section 8.2 Part 2: Analysis

While this comment could have been absorbed into the previous comment on this section, it is important to note that Hungerford specifies that does not imply that for every when dealing with groups and normal groups. 

I find it interesting that the statement for every , where $aNa^-1 ={ana^-1\mid n\in Na^-1 Na=Na\in G$$ are equivalent.