A question about centralizer of a vectors in the positive Weyl chamber

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Given a compact Lie group $K$ and a maximal torus $Tleq K$, and choose a positive Weyl chamber $mathfrak t^*_+subsetmathfrak k^*$, where we used a $K$-invariant inner product on $mathfrak k$. Then $mathfrak t^*_+$ can be decomposed into disjoint open faces
beginequation
mathfrak t^*_+=bigsqcup_sigmainSigmasigma
endequation
where $Sigma$ is the set of all faces.



Then question is about centralizer $K_xi$ of $xiinsigmainSigma$, do we have $K_xi$ only depends on $sigma$ and not depends on $xiinsigma$?







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    Given a compact Lie group $K$ and a maximal torus $Tleq K$, and choose a positive Weyl chamber $mathfrak t^*_+subsetmathfrak k^*$, where we used a $K$-invariant inner product on $mathfrak k$. Then $mathfrak t^*_+$ can be decomposed into disjoint open faces
    beginequation
    mathfrak t^*_+=bigsqcup_sigmainSigmasigma
    endequation
    where $Sigma$ is the set of all faces.



    Then question is about centralizer $K_xi$ of $xiinsigmainSigma$, do we have $K_xi$ only depends on $sigma$ and not depends on $xiinsigma$?







    share|cite|improve this question






















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      Given a compact Lie group $K$ and a maximal torus $Tleq K$, and choose a positive Weyl chamber $mathfrak t^*_+subsetmathfrak k^*$, where we used a $K$-invariant inner product on $mathfrak k$. Then $mathfrak t^*_+$ can be decomposed into disjoint open faces
      beginequation
      mathfrak t^*_+=bigsqcup_sigmainSigmasigma
      endequation
      where $Sigma$ is the set of all faces.



      Then question is about centralizer $K_xi$ of $xiinsigmainSigma$, do we have $K_xi$ only depends on $sigma$ and not depends on $xiinsigma$?







      share|cite|improve this question












      Given a compact Lie group $K$ and a maximal torus $Tleq K$, and choose a positive Weyl chamber $mathfrak t^*_+subsetmathfrak k^*$, where we used a $K$-invariant inner product on $mathfrak k$. Then $mathfrak t^*_+$ can be decomposed into disjoint open faces
      beginequation
      mathfrak t^*_+=bigsqcup_sigmainSigmasigma
      endequation
      where $Sigma$ is the set of all faces.



      Then question is about centralizer $K_xi$ of $xiinsigmainSigma$, do we have $K_xi$ only depends on $sigma$ and not depends on $xiinsigma$?









      share|cite|improve this question











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      asked Aug 9 at 8:11









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          The identity component of the centralizer depends only on the face, but the component group is more sensitive. For proof of these statements, an example of the dependence, and an explanation of how to compute both, I refer to §2.4 of Mark Reeder's excellent survey, "Torsion automorphisms of simple Lie algebras".






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            The identity component of the centralizer depends only on the face, but the component group is more sensitive. For proof of these statements, an example of the dependence, and an explanation of how to compute both, I refer to §2.4 of Mark Reeder's excellent survey, "Torsion automorphisms of simple Lie algebras".






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              up vote
              4
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              The identity component of the centralizer depends only on the face, but the component group is more sensitive. For proof of these statements, an example of the dependence, and an explanation of how to compute both, I refer to §2.4 of Mark Reeder's excellent survey, "Torsion automorphisms of simple Lie algebras".






              share|cite|improve this answer






















                up vote
                4
                down vote










                up vote
                4
                down vote









                The identity component of the centralizer depends only on the face, but the component group is more sensitive. For proof of these statements, an example of the dependence, and an explanation of how to compute both, I refer to §2.4 of Mark Reeder's excellent survey, "Torsion automorphisms of simple Lie algebras".






                share|cite|improve this answer












                The identity component of the centralizer depends only on the face, but the component group is more sensitive. For proof of these statements, an example of the dependence, and an explanation of how to compute both, I refer to §2.4 of Mark Reeder's excellent survey, "Torsion automorphisms of simple Lie algebras".







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                answered Aug 9 at 8:57









                Gro-Tsen

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