Projective spaces and flag manifolds











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Is the complex projective space $mathbb CP^2$ a flag variety? If yes, what are the complex semisimple Lie group $S$ and a parabolic subgroup $H$ such that $mathbb CP^2=S/H$?










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    The group is $SL_3$, and any maximal parabolic in it.
    – Sasha
    Nov 22 at 18:52










  • @Sasha So is it true in general that all projective spaces are flag manifolds?
    – Amrat A
    Nov 22 at 19:03






  • 2




    Yes, it is true in general.
    – Sasha
    Nov 22 at 19:12















up vote
0
down vote

favorite












Is the complex projective space $mathbb CP^2$ a flag variety? If yes, what are the complex semisimple Lie group $S$ and a parabolic subgroup $H$ such that $mathbb CP^2=S/H$?










share|cite|improve this question


















  • 2




    The group is $SL_3$, and any maximal parabolic in it.
    – Sasha
    Nov 22 at 18:52










  • @Sasha So is it true in general that all projective spaces are flag manifolds?
    – Amrat A
    Nov 22 at 19:03






  • 2




    Yes, it is true in general.
    – Sasha
    Nov 22 at 19:12













up vote
0
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favorite









up vote
0
down vote

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Is the complex projective space $mathbb CP^2$ a flag variety? If yes, what are the complex semisimple Lie group $S$ and a parabolic subgroup $H$ such that $mathbb CP^2=S/H$?










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Is the complex projective space $mathbb CP^2$ a flag variety? If yes, what are the complex semisimple Lie group $S$ and a parabolic subgroup $H$ such that $mathbb CP^2=S/H$?







differential-geometry algebraic-geometry lie-groups






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asked Nov 22 at 18:37









Amrat A

31818




31818








  • 2




    The group is $SL_3$, and any maximal parabolic in it.
    – Sasha
    Nov 22 at 18:52










  • @Sasha So is it true in general that all projective spaces are flag manifolds?
    – Amrat A
    Nov 22 at 19:03






  • 2




    Yes, it is true in general.
    – Sasha
    Nov 22 at 19:12














  • 2




    The group is $SL_3$, and any maximal parabolic in it.
    – Sasha
    Nov 22 at 18:52










  • @Sasha So is it true in general that all projective spaces are flag manifolds?
    – Amrat A
    Nov 22 at 19:03






  • 2




    Yes, it is true in general.
    – Sasha
    Nov 22 at 19:12








2




2




The group is $SL_3$, and any maximal parabolic in it.
– Sasha
Nov 22 at 18:52




The group is $SL_3$, and any maximal parabolic in it.
– Sasha
Nov 22 at 18:52












@Sasha So is it true in general that all projective spaces are flag manifolds?
– Amrat A
Nov 22 at 19:03




@Sasha So is it true in general that all projective spaces are flag manifolds?
– Amrat A
Nov 22 at 19:03




2




2




Yes, it is true in general.
– Sasha
Nov 22 at 19:12




Yes, it is true in general.
– Sasha
Nov 22 at 19:12










1 Answer
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More generally, for any sequence $d_1 < d_2 < dots < d_k < n$, the space of all partial flags $$V_1 subset V_2 subset dots subset V_k subset Bbb C^n$$



with $dim V_i = d_i$ has a transitive $SL_n(Bbb C)$-action. You can easily write down the stabiliser and more or less by definition it's a parabolic subgroup. Your question is the special case when $n=3, k=1$ and $d_1 = 1$.






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    1 Answer
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    active

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    1 Answer
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    active

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    active

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    active

    oldest

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    up vote
    0
    down vote



    accepted










    More generally, for any sequence $d_1 < d_2 < dots < d_k < n$, the space of all partial flags $$V_1 subset V_2 subset dots subset V_k subset Bbb C^n$$



    with $dim V_i = d_i$ has a transitive $SL_n(Bbb C)$-action. You can easily write down the stabiliser and more or less by definition it's a parabolic subgroup. Your question is the special case when $n=3, k=1$ and $d_1 = 1$.






    share|cite|improve this answer

























      up vote
      0
      down vote



      accepted










      More generally, for any sequence $d_1 < d_2 < dots < d_k < n$, the space of all partial flags $$V_1 subset V_2 subset dots subset V_k subset Bbb C^n$$



      with $dim V_i = d_i$ has a transitive $SL_n(Bbb C)$-action. You can easily write down the stabiliser and more or less by definition it's a parabolic subgroup. Your question is the special case when $n=3, k=1$ and $d_1 = 1$.






      share|cite|improve this answer























        up vote
        0
        down vote



        accepted







        up vote
        0
        down vote



        accepted






        More generally, for any sequence $d_1 < d_2 < dots < d_k < n$, the space of all partial flags $$V_1 subset V_2 subset dots subset V_k subset Bbb C^n$$



        with $dim V_i = d_i$ has a transitive $SL_n(Bbb C)$-action. You can easily write down the stabiliser and more or less by definition it's a parabolic subgroup. Your question is the special case when $n=3, k=1$ and $d_1 = 1$.






        share|cite|improve this answer












        More generally, for any sequence $d_1 < d_2 < dots < d_k < n$, the space of all partial flags $$V_1 subset V_2 subset dots subset V_k subset Bbb C^n$$



        with $dim V_i = d_i$ has a transitive $SL_n(Bbb C)$-action. You can easily write down the stabiliser and more or less by definition it's a parabolic subgroup. Your question is the special case when $n=3, k=1$ and $d_1 = 1$.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Nov 23 at 10:53









        Nicolas Hemelsoet

        5,7352417




        5,7352417






























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