MathDB
statements about subgroup

Source: LIMIT 2019 CCS1 P3

April 28, 2021
group theoryabstract algebra

Problem Statement

GG be a group and HGH\le G. Then which of the following are true? <spanclass=latexbold>(A)</span> aG,aHa1HaHa1=H<span class='latex-bold'>(A)</span>~a\in G,aHa^{-1}\subset H\Rightarrow aHa^{-1}=H <spanclass=latexbold>(B)</span> G,H and HG with HG<span class='latex-bold'>(B)</span>~\exists G,H\text{ and }H\le G\text{ with }H\cong G <spanclass=latexbold>(C)</span> All subgroups are normal, then G is abelian.<span class='latex-bold'>(C)</span>~\text{All subgroups are normal, then }G\text{ is abelian.} <spanclass=latexbold>(D)</span> None of the above<span class='latex-bold'>(D)</span>~\text{None of the above}