Is it true all centralizer of G are abelian?












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Suppose $G$ is a finite group such that $frac{G}{Z(G)}cong Z_ptimes Z_ptimes Z_p$.

Is it true all centralizers of G are abelian?










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  • $begingroup$
    I guess this is not true. Suppose we have found some nonabelian $G$ such that $G / Z(G) cong (Z/pZ)^3$. Then $C(Z(G)) = G$ which is nonabelian. The difficulty seems to be in finding such $G$ for each $p$.
    $endgroup$
    – Alex Vong
    Dec 9 '18 at 11:20


















1












$begingroup$


Suppose $G$ is a finite group such that $frac{G}{Z(G)}cong Z_ptimes Z_ptimes Z_p$.

Is it true all centralizers of G are abelian?










share|cite|improve this question









$endgroup$












  • $begingroup$
    I guess this is not true. Suppose we have found some nonabelian $G$ such that $G / Z(G) cong (Z/pZ)^3$. Then $C(Z(G)) = G$ which is nonabelian. The difficulty seems to be in finding such $G$ for each $p$.
    $endgroup$
    – Alex Vong
    Dec 9 '18 at 11:20
















1












1








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1



$begingroup$


Suppose $G$ is a finite group such that $frac{G}{Z(G)}cong Z_ptimes Z_ptimes Z_p$.

Is it true all centralizers of G are abelian?










share|cite|improve this question









$endgroup$




Suppose $G$ is a finite group such that $frac{G}{Z(G)}cong Z_ptimes Z_ptimes Z_p$.

Is it true all centralizers of G are abelian?







finite-groups






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asked Dec 9 '18 at 7:21









m a sm a s

333




333












  • $begingroup$
    I guess this is not true. Suppose we have found some nonabelian $G$ such that $G / Z(G) cong (Z/pZ)^3$. Then $C(Z(G)) = G$ which is nonabelian. The difficulty seems to be in finding such $G$ for each $p$.
    $endgroup$
    – Alex Vong
    Dec 9 '18 at 11:20




















  • $begingroup$
    I guess this is not true. Suppose we have found some nonabelian $G$ such that $G / Z(G) cong (Z/pZ)^3$. Then $C(Z(G)) = G$ which is nonabelian. The difficulty seems to be in finding such $G$ for each $p$.
    $endgroup$
    – Alex Vong
    Dec 9 '18 at 11:20


















$begingroup$
I guess this is not true. Suppose we have found some nonabelian $G$ such that $G / Z(G) cong (Z/pZ)^3$. Then $C(Z(G)) = G$ which is nonabelian. The difficulty seems to be in finding such $G$ for each $p$.
$endgroup$
– Alex Vong
Dec 9 '18 at 11:20






$begingroup$
I guess this is not true. Suppose we have found some nonabelian $G$ such that $G / Z(G) cong (Z/pZ)^3$. Then $C(Z(G)) = G$ which is nonabelian. The difficulty seems to be in finding such $G$ for each $p$.
$endgroup$
– Alex Vong
Dec 9 '18 at 11:20












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$begingroup$

As mentioned in the comments, if $G$ was non-abelian, then for $zin Z(G)$, $C(z)=G$ would be a contradiction. But of course, if $G$ is abelian, then $G/Z(G)$ is trivial. So your claim is equivalent to: there exists no finite group $G$ with $G/Z(G)=Z_p^3$.



That's probably a hint this isn't true. Since $G$ is nilpotent, we can restrict attention to finite $p$-groups. Then we can get a counterexample for every $p$:



Let $H$ be the elementary abelian group of order $p^3$, generated by $x,y,z$. Let $alpha,betain Aut(H)$ be two order $p$ elements:
begin{align*}
alpha(x) = xy && alpha(y)=y && alpha(z)=z\
beta(x)=xz && beta(y)=y && beta(z)=z
end{align*}

Then if $G$ is the group of order $p^5$, given by the semidirect product $Hrtimeslanglealpha,betarangle$, we have $Z(G)=langle y,zrangle$ and $G/Z(G)$ is the elementary abelian group generated by the images of $x$, $alpha$, and $beta$.






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    $begingroup$

    As mentioned in the comments, if $G$ was non-abelian, then for $zin Z(G)$, $C(z)=G$ would be a contradiction. But of course, if $G$ is abelian, then $G/Z(G)$ is trivial. So your claim is equivalent to: there exists no finite group $G$ with $G/Z(G)=Z_p^3$.



    That's probably a hint this isn't true. Since $G$ is nilpotent, we can restrict attention to finite $p$-groups. Then we can get a counterexample for every $p$:



    Let $H$ be the elementary abelian group of order $p^3$, generated by $x,y,z$. Let $alpha,betain Aut(H)$ be two order $p$ elements:
    begin{align*}
    alpha(x) = xy && alpha(y)=y && alpha(z)=z\
    beta(x)=xz && beta(y)=y && beta(z)=z
    end{align*}

    Then if $G$ is the group of order $p^5$, given by the semidirect product $Hrtimeslanglealpha,betarangle$, we have $Z(G)=langle y,zrangle$ and $G/Z(G)$ is the elementary abelian group generated by the images of $x$, $alpha$, and $beta$.






    share|cite|improve this answer









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      2












      $begingroup$

      As mentioned in the comments, if $G$ was non-abelian, then for $zin Z(G)$, $C(z)=G$ would be a contradiction. But of course, if $G$ is abelian, then $G/Z(G)$ is trivial. So your claim is equivalent to: there exists no finite group $G$ with $G/Z(G)=Z_p^3$.



      That's probably a hint this isn't true. Since $G$ is nilpotent, we can restrict attention to finite $p$-groups. Then we can get a counterexample for every $p$:



      Let $H$ be the elementary abelian group of order $p^3$, generated by $x,y,z$. Let $alpha,betain Aut(H)$ be two order $p$ elements:
      begin{align*}
      alpha(x) = xy && alpha(y)=y && alpha(z)=z\
      beta(x)=xz && beta(y)=y && beta(z)=z
      end{align*}

      Then if $G$ is the group of order $p^5$, given by the semidirect product $Hrtimeslanglealpha,betarangle$, we have $Z(G)=langle y,zrangle$ and $G/Z(G)$ is the elementary abelian group generated by the images of $x$, $alpha$, and $beta$.






      share|cite|improve this answer









      $endgroup$
















        2












        2








        2





        $begingroup$

        As mentioned in the comments, if $G$ was non-abelian, then for $zin Z(G)$, $C(z)=G$ would be a contradiction. But of course, if $G$ is abelian, then $G/Z(G)$ is trivial. So your claim is equivalent to: there exists no finite group $G$ with $G/Z(G)=Z_p^3$.



        That's probably a hint this isn't true. Since $G$ is nilpotent, we can restrict attention to finite $p$-groups. Then we can get a counterexample for every $p$:



        Let $H$ be the elementary abelian group of order $p^3$, generated by $x,y,z$. Let $alpha,betain Aut(H)$ be two order $p$ elements:
        begin{align*}
        alpha(x) = xy && alpha(y)=y && alpha(z)=z\
        beta(x)=xz && beta(y)=y && beta(z)=z
        end{align*}

        Then if $G$ is the group of order $p^5$, given by the semidirect product $Hrtimeslanglealpha,betarangle$, we have $Z(G)=langle y,zrangle$ and $G/Z(G)$ is the elementary abelian group generated by the images of $x$, $alpha$, and $beta$.






        share|cite|improve this answer









        $endgroup$



        As mentioned in the comments, if $G$ was non-abelian, then for $zin Z(G)$, $C(z)=G$ would be a contradiction. But of course, if $G$ is abelian, then $G/Z(G)$ is trivial. So your claim is equivalent to: there exists no finite group $G$ with $G/Z(G)=Z_p^3$.



        That's probably a hint this isn't true. Since $G$ is nilpotent, we can restrict attention to finite $p$-groups. Then we can get a counterexample for every $p$:



        Let $H$ be the elementary abelian group of order $p^3$, generated by $x,y,z$. Let $alpha,betain Aut(H)$ be two order $p$ elements:
        begin{align*}
        alpha(x) = xy && alpha(y)=y && alpha(z)=z\
        beta(x)=xz && beta(y)=y && beta(z)=z
        end{align*}

        Then if $G$ is the group of order $p^5$, given by the semidirect product $Hrtimeslanglealpha,betarangle$, we have $Z(G)=langle y,zrangle$ and $G/Z(G)$ is the elementary abelian group generated by the images of $x$, $alpha$, and $beta$.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Dec 10 '18 at 5:44









        HempeliciousHempelicious

        147110




        147110






























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