## chief factor of finite group

 Mentor Blog Entries: 8 Take $x\in L$. Then there is a g in G such that $x\in T^g$ and thus there is a y in T such that $x=gyg^{-1}$. If x has order p or order 4, then so does y. But by the previous sentence, y is contained in K. Since K is normal, we have that also x is in K.
 The symbol $L=\bigcup_{g \in G} T^{g}$, does it mean the union of sets or $L=$and, if it the union of sets, then how did he gets that $L$ equals to that union?