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Compute dimensions of simple symmetric group modules over positive characteristic #36724

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merged 2 commits into from
Dec 10, 2023

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@tscrim tscrim commented Nov 15, 2023

We can compute Specht module dimensions, but an interesting open problem is to compute the dimensions of simple modules for S_n over fields of positive characteristic. We provide a way to compute dimensions by using the pullback of the polytabloid inner product and computing the rank of the Gram matrix.

This is based off of code provided by Jackson Walters.

We also implement a more efficient column stabilizer method for standard tableaux.

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ok, good

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tscrim commented Nov 17, 2023

Thank you!

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Documentation preview for this PR (built with commit 721b952; changes) is ready! 🎉

@vbraun vbraun merged commit 27dc76a into sagemath:develop Dec 10, 2023
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@mkoeppe mkoeppe added this to the sage-10.3 milestone Dec 10, 2023
@tscrim tscrim deleted the combinat/specht_mod_dim branch December 28, 2023 05:12
vbraun pushed a commit to vbraun/sage that referenced this pull request Mar 24, 2024
    
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This provides an implementation of the Specht modules over arbitrary
fields in the standard tableaux basis. To do so, we also implement the
tabloid module, where the tabloids are implemented as
`OrderedSetsPartitions`. Using this, we can construct the maximal
submodule and simple submodule from a Specht module.

We also implement a method to compute the Brauer character of the
representations.

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### ⌛ Dependencies

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- sagemath#36724: Trivial conflict with working on the same files.
- sagemath#36985: So the 0 dimensional tests will pass.

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URL: sagemath#36748
Reported by: Travis Scrimshaw
Reviewer(s): Darij Grinberg, Frédéric Chapoton, Martin Rubey, Travis Scrimshaw
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4 participants