What is the definition of a minimal presentation of a group?












3












$begingroup$


I'm working on a problem on the braid monodromy of complex lines arrangements in $mathbb{C}^{2}.$ I have the following question. It's just a simple definition. However, I didn't find anywhere.




Let $G$ be a group and let $langle Smid Rrangle$ be a presentation of $G.$ What does it mean that such presentation is minimal?




Thank you very much for everyone will answer and kind regards.










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$endgroup$








  • 1




    $begingroup$
    In most cases, if the group is finite-generated then minimality if referd to the cardinality of $|S|$. That is a presentation is minimal if $S$ is a minimal set of generators.
    $endgroup$
    – Ofir Schnabel
    Jan 21 '15 at 10:58






  • 1




    $begingroup$
    And what about the number of relators?
    $endgroup$
    – esaini582
    Jan 21 '15 at 13:21
















3












$begingroup$


I'm working on a problem on the braid monodromy of complex lines arrangements in $mathbb{C}^{2}.$ I have the following question. It's just a simple definition. However, I didn't find anywhere.




Let $G$ be a group and let $langle Smid Rrangle$ be a presentation of $G.$ What does it mean that such presentation is minimal?




Thank you very much for everyone will answer and kind regards.










share|cite|improve this question











$endgroup$








  • 1




    $begingroup$
    In most cases, if the group is finite-generated then minimality if referd to the cardinality of $|S|$. That is a presentation is minimal if $S$ is a minimal set of generators.
    $endgroup$
    – Ofir Schnabel
    Jan 21 '15 at 10:58






  • 1




    $begingroup$
    And what about the number of relators?
    $endgroup$
    – esaini582
    Jan 21 '15 at 13:21














3












3








3





$begingroup$


I'm working on a problem on the braid monodromy of complex lines arrangements in $mathbb{C}^{2}.$ I have the following question. It's just a simple definition. However, I didn't find anywhere.




Let $G$ be a group and let $langle Smid Rrangle$ be a presentation of $G.$ What does it mean that such presentation is minimal?




Thank you very much for everyone will answer and kind regards.










share|cite|improve this question











$endgroup$




I'm working on a problem on the braid monodromy of complex lines arrangements in $mathbb{C}^{2}.$ I have the following question. It's just a simple definition. However, I didn't find anywhere.




Let $G$ be a group and let $langle Smid Rrangle$ be a presentation of $G.$ What does it mean that such presentation is minimal?




Thank you very much for everyone will answer and kind regards.







definition group-presentation combinatorial-group-theory






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share|cite|improve this question













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share|cite|improve this question








edited Nov 29 '18 at 22:50









Shaun

9,083113683




9,083113683










asked Jan 20 '15 at 16:17









esaini582esaini582

2009




2009








  • 1




    $begingroup$
    In most cases, if the group is finite-generated then minimality if referd to the cardinality of $|S|$. That is a presentation is minimal if $S$ is a minimal set of generators.
    $endgroup$
    – Ofir Schnabel
    Jan 21 '15 at 10:58






  • 1




    $begingroup$
    And what about the number of relators?
    $endgroup$
    – esaini582
    Jan 21 '15 at 13:21














  • 1




    $begingroup$
    In most cases, if the group is finite-generated then minimality if referd to the cardinality of $|S|$. That is a presentation is minimal if $S$ is a minimal set of generators.
    $endgroup$
    – Ofir Schnabel
    Jan 21 '15 at 10:58






  • 1




    $begingroup$
    And what about the number of relators?
    $endgroup$
    – esaini582
    Jan 21 '15 at 13:21








1




1




$begingroup$
In most cases, if the group is finite-generated then minimality if referd to the cardinality of $|S|$. That is a presentation is minimal if $S$ is a minimal set of generators.
$endgroup$
– Ofir Schnabel
Jan 21 '15 at 10:58




$begingroup$
In most cases, if the group is finite-generated then minimality if referd to the cardinality of $|S|$. That is a presentation is minimal if $S$ is a minimal set of generators.
$endgroup$
– Ofir Schnabel
Jan 21 '15 at 10:58




1




1




$begingroup$
And what about the number of relators?
$endgroup$
– esaini582
Jan 21 '15 at 13:21




$begingroup$
And what about the number of relators?
$endgroup$
– esaini582
Jan 21 '15 at 13:21










1 Answer
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$begingroup$

Quoting this question:




For a finite group $G$ let $d(G)$ be the minimal number of generators of $G$ and let $r(G)$ be the minimal number such that $G$ has a finite presentation with $r(G)$ relators. Call a presentation with $d(G)$ generators and $r(G)$ relators a minimal presentation.




So, using your notation, both $|S|$ and $|R|$ are the smallest they can be for $langle Smid Rrangle$ to be a presentation of $G$.






share|cite|improve this answer









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    1 Answer
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    $begingroup$

    Quoting this question:




    For a finite group $G$ let $d(G)$ be the minimal number of generators of $G$ and let $r(G)$ be the minimal number such that $G$ has a finite presentation with $r(G)$ relators. Call a presentation with $d(G)$ generators and $r(G)$ relators a minimal presentation.




    So, using your notation, both $|S|$ and $|R|$ are the smallest they can be for $langle Smid Rrangle$ to be a presentation of $G$.






    share|cite|improve this answer









    $endgroup$


















      0












      $begingroup$

      Quoting this question:




      For a finite group $G$ let $d(G)$ be the minimal number of generators of $G$ and let $r(G)$ be the minimal number such that $G$ has a finite presentation with $r(G)$ relators. Call a presentation with $d(G)$ generators and $r(G)$ relators a minimal presentation.




      So, using your notation, both $|S|$ and $|R|$ are the smallest they can be for $langle Smid Rrangle$ to be a presentation of $G$.






      share|cite|improve this answer









      $endgroup$
















        0












        0








        0





        $begingroup$

        Quoting this question:




        For a finite group $G$ let $d(G)$ be the minimal number of generators of $G$ and let $r(G)$ be the minimal number such that $G$ has a finite presentation with $r(G)$ relators. Call a presentation with $d(G)$ generators and $r(G)$ relators a minimal presentation.




        So, using your notation, both $|S|$ and $|R|$ are the smallest they can be for $langle Smid Rrangle$ to be a presentation of $G$.






        share|cite|improve this answer









        $endgroup$



        Quoting this question:




        For a finite group $G$ let $d(G)$ be the minimal number of generators of $G$ and let $r(G)$ be the minimal number such that $G$ has a finite presentation with $r(G)$ relators. Call a presentation with $d(G)$ generators and $r(G)$ relators a minimal presentation.




        So, using your notation, both $|S|$ and $|R|$ are the smallest they can be for $langle Smid Rrangle$ to be a presentation of $G$.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Nov 29 '18 at 22:48









        ShaunShaun

        9,083113683




        9,083113683






























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