[HN Gopher] Young Diagrams and Classical Groups [pdf]
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       Young Diagrams and Classical Groups [pdf]
        
       Author : gbrown_
       Score  : 33 points
       Date   : 2022-09-25 11:24 UTC (1 days ago)
        
 (HTM) web link (math.ucr.edu)
 (TXT) w3m dump (math.ucr.edu)
        
       | ShuffleBoard wrote:
       | Awesome! Thank you!
        
       | generationP wrote:
       | I knew Craige Schensted left his mark on the subject; I had no
       | idea his wife (Irene Verona Schensted) had written a book about
       | it! (well, I think it's about it; it's not on libgen...)
        
       | adamnemecek wrote:
       | The underlying idea is the idea of fixed points (aka spectra,
       | diagonalizations, embedding, invariants, braids). By fixed point
       | I mean something like the "Lawvere's fixed point theorem".
       | https://ncatlab.org/nlab/show/Lawvere%27s+fixed+point+theore...
       | 
       | I have a linkdump on this
       | 
       | https://github.com/adamnemecek/adjoint
       | 
       | I also have a discord https://discord.gg/mr9TAhpyBW
        
         | generationP wrote:
         | The only two 1-dimensional representations of the symmetric
         | group (i.e., what you can call fixed points if you squint a
         | bit) are the ones that correspond to the partitions (n) and
         | (1,1,...,1), which are the least interesting ones. Everything
         | else is significantly more complicated. It's a block-
         | diagonalization (Young seminormal form) with lots of nontrivial
         | blocks. So no, you won't understand it in terms of fixed points
         | (and certainly not of Lawvere's theorem, which I've never seen
         | used in the entire subject).
        
         | klysm wrote:
         | What's the discord for?
        
           | adamnemecek wrote:
           | Further discussion.
        
             | klysm wrote:
             | About what specifically
        
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       (page generated 2022-09-26 23:02 UTC)