refresh Symmetric Group representations

[Frédéric Chapoton]

as part of #12913

to get rid of CombinatorialClass

[Frédéric Chapoton]

Here is a first tentative, still failing. Needs help for investigating.

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New commits:

​856fa06

first work on symmetric group representations

[Travis Scrimshaw]

You need to pass the parent to construct the representation/element. The generic parent SymmetricGroupRepresentations_class does not know about what the default ring should be. This is something set by the subclasses. I see two options:

1 - Implement a proper parent/element system with rewriting the (internal) construction paths to use P.element_class for the appropriate parent P. 2 - Just pass the correct object during the call of SymmetricGroupRepresentation.

1 takes more work, but it is the proper way to do it. 2 is quick and will work for now. I don't think 1 is too much more work, and I can do it if you want.

[Frédéric Chapoton]

Hello, I am not sure that I am able to do either of what you propose. If you can, please do. Otherwise, I will try later.

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​6f5da42

Putting symmetric group reprs fully into the category framework.

[git]

Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:

​e6bfc93

Putting symmetric group reprs fully into the category framework.

[Travis Scrimshaw]

Okay, here is a working branch.

[Frédéric Chapoton]

good, morally green bot and the changes looks good. I am setting to positive.