Def. Let H⊂GH \subset GH⊂G Subgroup. For every $g∈Gg \in Gg∈G, we can define the conjugate subgroup gHg−1={ghg−1∣h∈H}gHg^{-1} = \{ ghg^{-1}| h \in H\}gHg−1={ghg−1∣h∈H}.