Sylow $p$-subgroups of Galois group

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It just my curious, but I couldn’t find any related concept:



Condition)




Let $G$ be a finite Galois group, and the number of each Sylow $p_i$-subgroup of $G$ is one, where $p_i$ is a prime factor of $|G|$.




Question)



Under the above condition, is it true $G$ is cyclic?



Give some advice or related notion! Thank you!







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  • 3




    All Sylow subgroups being normal is well known to be equivalent to the group $G$ being nilpotent. There are non-cyclic nilpotent groups. In fact every $p$-group is nilpotent ...
    – Jyrki Lahtonen
    Jul 27 at 5:33










  • @JyrkiLahtonen Actually, I was solving the following problems: Let $K$ be a Galois extension over $mathbbQ$ with $[K:mathbbQ]=540$, let $G:=G(K/mathbbQ)$ be the Galois group so that the number of each Sylow subgroup of $G$ is one. I don't know who made it, the solution of the above problem claims that $G$ is cyclic without any proof. I don't understand how to guarantee $G$ is cyclic. Since $Gcong P_2times P_3times P_5$, where each $P_i$ is a Sylow $i$-subgroup of $G$, I think there is no guarantee that $G$ is cyclic. Is there something I missed?
    – Primavera
    Jul 27 at 14:32











  • $540=2^2cdot3^3cdot5$. There are non-cyclic groups of orders $2^2$ and $3^3$, so you cannot conclude that $G$ would be cyclic based on that piece of data alone. Yes, something is missing from that exercise.
    – Jyrki Lahtonen
    Jul 27 at 14:48















up vote
0
down vote

favorite












It just my curious, but I couldn’t find any related concept:



Condition)




Let $G$ be a finite Galois group, and the number of each Sylow $p_i$-subgroup of $G$ is one, where $p_i$ is a prime factor of $|G|$.




Question)



Under the above condition, is it true $G$ is cyclic?



Give some advice or related notion! Thank you!







share|cite|improve this question

















  • 3




    All Sylow subgroups being normal is well known to be equivalent to the group $G$ being nilpotent. There are non-cyclic nilpotent groups. In fact every $p$-group is nilpotent ...
    – Jyrki Lahtonen
    Jul 27 at 5:33










  • @JyrkiLahtonen Actually, I was solving the following problems: Let $K$ be a Galois extension over $mathbbQ$ with $[K:mathbbQ]=540$, let $G:=G(K/mathbbQ)$ be the Galois group so that the number of each Sylow subgroup of $G$ is one. I don't know who made it, the solution of the above problem claims that $G$ is cyclic without any proof. I don't understand how to guarantee $G$ is cyclic. Since $Gcong P_2times P_3times P_5$, where each $P_i$ is a Sylow $i$-subgroup of $G$, I think there is no guarantee that $G$ is cyclic. Is there something I missed?
    – Primavera
    Jul 27 at 14:32











  • $540=2^2cdot3^3cdot5$. There are non-cyclic groups of orders $2^2$ and $3^3$, so you cannot conclude that $G$ would be cyclic based on that piece of data alone. Yes, something is missing from that exercise.
    – Jyrki Lahtonen
    Jul 27 at 14:48













up vote
0
down vote

favorite









up vote
0
down vote

favorite











It just my curious, but I couldn’t find any related concept:



Condition)




Let $G$ be a finite Galois group, and the number of each Sylow $p_i$-subgroup of $G$ is one, where $p_i$ is a prime factor of $|G|$.




Question)



Under the above condition, is it true $G$ is cyclic?



Give some advice or related notion! Thank you!







share|cite|improve this question













It just my curious, but I couldn’t find any related concept:



Condition)




Let $G$ be a finite Galois group, and the number of each Sylow $p_i$-subgroup of $G$ is one, where $p_i$ is a prime factor of $|G|$.




Question)



Under the above condition, is it true $G$ is cyclic?



Give some advice or related notion! Thank you!









share|cite|improve this question












share|cite|improve this question




share|cite|improve this question








edited Jul 27 at 8:53









Bernard

110k635102




110k635102









asked Jul 27 at 5:23









Primavera

1548




1548







  • 3




    All Sylow subgroups being normal is well known to be equivalent to the group $G$ being nilpotent. There are non-cyclic nilpotent groups. In fact every $p$-group is nilpotent ...
    – Jyrki Lahtonen
    Jul 27 at 5:33










  • @JyrkiLahtonen Actually, I was solving the following problems: Let $K$ be a Galois extension over $mathbbQ$ with $[K:mathbbQ]=540$, let $G:=G(K/mathbbQ)$ be the Galois group so that the number of each Sylow subgroup of $G$ is one. I don't know who made it, the solution of the above problem claims that $G$ is cyclic without any proof. I don't understand how to guarantee $G$ is cyclic. Since $Gcong P_2times P_3times P_5$, where each $P_i$ is a Sylow $i$-subgroup of $G$, I think there is no guarantee that $G$ is cyclic. Is there something I missed?
    – Primavera
    Jul 27 at 14:32











  • $540=2^2cdot3^3cdot5$. There are non-cyclic groups of orders $2^2$ and $3^3$, so you cannot conclude that $G$ would be cyclic based on that piece of data alone. Yes, something is missing from that exercise.
    – Jyrki Lahtonen
    Jul 27 at 14:48













  • 3




    All Sylow subgroups being normal is well known to be equivalent to the group $G$ being nilpotent. There are non-cyclic nilpotent groups. In fact every $p$-group is nilpotent ...
    – Jyrki Lahtonen
    Jul 27 at 5:33










  • @JyrkiLahtonen Actually, I was solving the following problems: Let $K$ be a Galois extension over $mathbbQ$ with $[K:mathbbQ]=540$, let $G:=G(K/mathbbQ)$ be the Galois group so that the number of each Sylow subgroup of $G$ is one. I don't know who made it, the solution of the above problem claims that $G$ is cyclic without any proof. I don't understand how to guarantee $G$ is cyclic. Since $Gcong P_2times P_3times P_5$, where each $P_i$ is a Sylow $i$-subgroup of $G$, I think there is no guarantee that $G$ is cyclic. Is there something I missed?
    – Primavera
    Jul 27 at 14:32











  • $540=2^2cdot3^3cdot5$. There are non-cyclic groups of orders $2^2$ and $3^3$, so you cannot conclude that $G$ would be cyclic based on that piece of data alone. Yes, something is missing from that exercise.
    – Jyrki Lahtonen
    Jul 27 at 14:48








3




3




All Sylow subgroups being normal is well known to be equivalent to the group $G$ being nilpotent. There are non-cyclic nilpotent groups. In fact every $p$-group is nilpotent ...
– Jyrki Lahtonen
Jul 27 at 5:33




All Sylow subgroups being normal is well known to be equivalent to the group $G$ being nilpotent. There are non-cyclic nilpotent groups. In fact every $p$-group is nilpotent ...
– Jyrki Lahtonen
Jul 27 at 5:33












@JyrkiLahtonen Actually, I was solving the following problems: Let $K$ be a Galois extension over $mathbbQ$ with $[K:mathbbQ]=540$, let $G:=G(K/mathbbQ)$ be the Galois group so that the number of each Sylow subgroup of $G$ is one. I don't know who made it, the solution of the above problem claims that $G$ is cyclic without any proof. I don't understand how to guarantee $G$ is cyclic. Since $Gcong P_2times P_3times P_5$, where each $P_i$ is a Sylow $i$-subgroup of $G$, I think there is no guarantee that $G$ is cyclic. Is there something I missed?
– Primavera
Jul 27 at 14:32





@JyrkiLahtonen Actually, I was solving the following problems: Let $K$ be a Galois extension over $mathbbQ$ with $[K:mathbbQ]=540$, let $G:=G(K/mathbbQ)$ be the Galois group so that the number of each Sylow subgroup of $G$ is one. I don't know who made it, the solution of the above problem claims that $G$ is cyclic without any proof. I don't understand how to guarantee $G$ is cyclic. Since $Gcong P_2times P_3times P_5$, where each $P_i$ is a Sylow $i$-subgroup of $G$, I think there is no guarantee that $G$ is cyclic. Is there something I missed?
– Primavera
Jul 27 at 14:32













$540=2^2cdot3^3cdot5$. There are non-cyclic groups of orders $2^2$ and $3^3$, so you cannot conclude that $G$ would be cyclic based on that piece of data alone. Yes, something is missing from that exercise.
– Jyrki Lahtonen
Jul 27 at 14:48





$540=2^2cdot3^3cdot5$. There are non-cyclic groups of orders $2^2$ and $3^3$, so you cannot conclude that $G$ would be cyclic based on that piece of data alone. Yes, something is missing from that exercise.
– Jyrki Lahtonen
Jul 27 at 14:48











1 Answer
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up vote
4
down vote













Every finite group is a Galois group of some finite extension $L/K$
of fields.



If a finite group has a unique Sylow subgroup for each prime, then all
one can conclude is that it is nilpotent, that is a direct
product of $p$-groups. It need not be cyclic, or indeed Abelian.






share|cite|improve this answer





















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    1 Answer
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    active

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    up vote
    4
    down vote













    Every finite group is a Galois group of some finite extension $L/K$
    of fields.



    If a finite group has a unique Sylow subgroup for each prime, then all
    one can conclude is that it is nilpotent, that is a direct
    product of $p$-groups. It need not be cyclic, or indeed Abelian.






    share|cite|improve this answer

























      up vote
      4
      down vote













      Every finite group is a Galois group of some finite extension $L/K$
      of fields.



      If a finite group has a unique Sylow subgroup for each prime, then all
      one can conclude is that it is nilpotent, that is a direct
      product of $p$-groups. It need not be cyclic, or indeed Abelian.






      share|cite|improve this answer























        up vote
        4
        down vote










        up vote
        4
        down vote









        Every finite group is a Galois group of some finite extension $L/K$
        of fields.



        If a finite group has a unique Sylow subgroup for each prime, then all
        one can conclude is that it is nilpotent, that is a direct
        product of $p$-groups. It need not be cyclic, or indeed Abelian.






        share|cite|improve this answer













        Every finite group is a Galois group of some finite extension $L/K$
        of fields.



        If a finite group has a unique Sylow subgroup for each prime, then all
        one can conclude is that it is nilpotent, that is a direct
        product of $p$-groups. It need not be cyclic, or indeed Abelian.







        share|cite|improve this answer













        share|cite|improve this answer



        share|cite|improve this answer











        answered Jul 27 at 5:33









        Lord Shark the Unknown

        84.6k950111




        84.6k950111






















             

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