Tensor methods for representations of SU(n)












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I'm familiar with the Young Tableaux method for finding irreducible representations of $mathrm{SU}(n)$ for $ninmathbb{N}$, and I also know of the tensor methods for finding irreducible representations of $mathrm{SU}(3)$.



Tensor methods for $mathrm{SU}(3)$ seem to rely heavily on the fact that irreducible representations of this group are identified by two natural numbers $(p,q)$, which define the covariance and contravariance of the tensor associated with that representation. But, if I'm not wrong, and, $n-1$ are needed to identify every irreducible representation of $mathrm{SU}(n)$. I have no proof of this but it makes sense if we look at the Young Tableaux method.



My questions, then, are:




  • Do tensor methods for finding irreducible representations of $mathrm{SU}(n)$ exist for $n > 3$?


  • If so, which are those?


  • If not, how is it that they exist for $n leq 3$, why do they work?











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  • $begingroup$
    The irreducible representations are determined by their restriction to a maximal torus which has dimension $n-1$, these are the weights.
    $endgroup$
    – Charlie Frohman
    Jan 29 at 2:27






  • 1




    $begingroup$
    Yes, these are the Dynkin indices: the number of single boxes, two-box columns, 3-box columns...etc. You want a tutorial? Slansky 1981.
    $endgroup$
    – Cosmas Zachos
    Feb 4 at 0:01
















0












$begingroup$


I'm familiar with the Young Tableaux method for finding irreducible representations of $mathrm{SU}(n)$ for $ninmathbb{N}$, and I also know of the tensor methods for finding irreducible representations of $mathrm{SU}(3)$.



Tensor methods for $mathrm{SU}(3)$ seem to rely heavily on the fact that irreducible representations of this group are identified by two natural numbers $(p,q)$, which define the covariance and contravariance of the tensor associated with that representation. But, if I'm not wrong, and, $n-1$ are needed to identify every irreducible representation of $mathrm{SU}(n)$. I have no proof of this but it makes sense if we look at the Young Tableaux method.



My questions, then, are:




  • Do tensor methods for finding irreducible representations of $mathrm{SU}(n)$ exist for $n > 3$?


  • If so, which are those?


  • If not, how is it that they exist for $n leq 3$, why do they work?











share|cite|improve this question











$endgroup$












  • $begingroup$
    The irreducible representations are determined by their restriction to a maximal torus which has dimension $n-1$, these are the weights.
    $endgroup$
    – Charlie Frohman
    Jan 29 at 2:27






  • 1




    $begingroup$
    Yes, these are the Dynkin indices: the number of single boxes, two-box columns, 3-box columns...etc. You want a tutorial? Slansky 1981.
    $endgroup$
    – Cosmas Zachos
    Feb 4 at 0:01














0












0








0





$begingroup$


I'm familiar with the Young Tableaux method for finding irreducible representations of $mathrm{SU}(n)$ for $ninmathbb{N}$, and I also know of the tensor methods for finding irreducible representations of $mathrm{SU}(3)$.



Tensor methods for $mathrm{SU}(3)$ seem to rely heavily on the fact that irreducible representations of this group are identified by two natural numbers $(p,q)$, which define the covariance and contravariance of the tensor associated with that representation. But, if I'm not wrong, and, $n-1$ are needed to identify every irreducible representation of $mathrm{SU}(n)$. I have no proof of this but it makes sense if we look at the Young Tableaux method.



My questions, then, are:




  • Do tensor methods for finding irreducible representations of $mathrm{SU}(n)$ exist for $n > 3$?


  • If so, which are those?


  • If not, how is it that they exist for $n leq 3$, why do they work?











share|cite|improve this question











$endgroup$




I'm familiar with the Young Tableaux method for finding irreducible representations of $mathrm{SU}(n)$ for $ninmathbb{N}$, and I also know of the tensor methods for finding irreducible representations of $mathrm{SU}(3)$.



Tensor methods for $mathrm{SU}(3)$ seem to rely heavily on the fact that irreducible representations of this group are identified by two natural numbers $(p,q)$, which define the covariance and contravariance of the tensor associated with that representation. But, if I'm not wrong, and, $n-1$ are needed to identify every irreducible representation of $mathrm{SU}(n)$. I have no proof of this but it makes sense if we look at the Young Tableaux method.



My questions, then, are:




  • Do tensor methods for finding irreducible representations of $mathrm{SU}(n)$ exist for $n > 3$?


  • If so, which are those?


  • If not, how is it that they exist for $n leq 3$, why do they work?








representation-theory lie-groups tensors






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edited Feb 2 at 16:58







TeicDaun

















asked Jan 28 at 22:38









TeicDaunTeicDaun

31116




31116












  • $begingroup$
    The irreducible representations are determined by their restriction to a maximal torus which has dimension $n-1$, these are the weights.
    $endgroup$
    – Charlie Frohman
    Jan 29 at 2:27






  • 1




    $begingroup$
    Yes, these are the Dynkin indices: the number of single boxes, two-box columns, 3-box columns...etc. You want a tutorial? Slansky 1981.
    $endgroup$
    – Cosmas Zachos
    Feb 4 at 0:01


















  • $begingroup$
    The irreducible representations are determined by their restriction to a maximal torus which has dimension $n-1$, these are the weights.
    $endgroup$
    – Charlie Frohman
    Jan 29 at 2:27






  • 1




    $begingroup$
    Yes, these are the Dynkin indices: the number of single boxes, two-box columns, 3-box columns...etc. You want a tutorial? Slansky 1981.
    $endgroup$
    – Cosmas Zachos
    Feb 4 at 0:01
















$begingroup$
The irreducible representations are determined by their restriction to a maximal torus which has dimension $n-1$, these are the weights.
$endgroup$
– Charlie Frohman
Jan 29 at 2:27




$begingroup$
The irreducible representations are determined by their restriction to a maximal torus which has dimension $n-1$, these are the weights.
$endgroup$
– Charlie Frohman
Jan 29 at 2:27




1




1




$begingroup$
Yes, these are the Dynkin indices: the number of single boxes, two-box columns, 3-box columns...etc. You want a tutorial? Slansky 1981.
$endgroup$
– Cosmas Zachos
Feb 4 at 0:01




$begingroup$
Yes, these are the Dynkin indices: the number of single boxes, two-box columns, 3-box columns...etc. You want a tutorial? Slansky 1981.
$endgroup$
– Cosmas Zachos
Feb 4 at 0:01










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