-
-
Notifications
You must be signed in to change notification settings - Fork 421
New issue
Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.
By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.
Already on GitHub? Sign in to your account
Adding cellular bases for the SymmetricGroupAlgebra over general fields #36718
Conversation
@fchapoton I hope you can do the review for this. Mathematically it is just implementing the KL |
there are a few failing doctests, some trivial and other less so |
This should fix all of the failing doctests. They were all trivial coming from the fact that the cell poset was in the reverse order. |
testing wihtout coxeter3 does not work:
|
4b2d1c2
to
3dc8791
Compare
Good catch. This should fix it. |
Documentation preview for this PR (built with commit 2e492e9; changes) is ready! 🎉 |
There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others. Learn more.
works with and without coxeter3, ok
Merci |
<!-- ^^^^^ Please provide a concise, informative and self-explanatory title. Don't put issue numbers in there, do this in the PR body below. For example, instead of "Fixes sagemath#1234" use "Introduce new method to calculate 1+1" --> <!-- Describe your changes here in detail --> We implement the Murphy basis of the symmetric group algebra (as defined by Dipper-James-Mathas) and make this the default cellular basis over positive characteristic since it is (significantly) faster to compute the change of basis necessary. <!-- Why is this change required? What problem does it solve? --> <!-- If this PR resolves an open issue, please link to it here. For example "Fixes sagemath#12345". --> <!-- If your change requires a documentation PR, please link it appropriately. --> ### 📝 Checklist <!-- Put an `x` in all the boxes that apply. --> <!-- If your change requires a documentation PR, please link it appropriately --> <!-- If you're unsure about any of these, don't hesitate to ask. We're here to help! --> <!-- Feel free to remove irrelevant items. --> - [x] The title is concise, informative, and self-explanatory. - [x] The description explains in detail what this PR is about. - [x] I have linked a relevant issue or discussion. - [x] I have created tests covering the changes. - [x] I have updated the documentation accordingly. ### ⌛ Dependencies <!-- List all open PRs that this PR logically depends on - sagemath#12345: short description why this is a dependency - sagemath#34567: ... --> - sagemath#36718 Uses the KL basis implementation <!-- If you're unsure about any of these, don't hesitate to ask. We're here to help! --> URL: sagemath#36790 Reported by: Travis Scrimshaw Reviewer(s): Frédéric Chapoton
<!-- ^^^^^ Please provide a concise, informative and self-explanatory title. Don't put issue numbers in there, do this in the PR body below. For example, instead of "Fixes sagemath#1234" use "Introduce new method to calculate 1+1" --> <!-- Describe your changes here in detail --> We implement the Murphy basis of the symmetric group algebra (as defined by Dipper-James-Mathas) and make this the default cellular basis over positive characteristic since it is (significantly) faster to compute the change of basis necessary. <!-- Why is this change required? What problem does it solve? --> <!-- If this PR resolves an open issue, please link to it here. For example "Fixes sagemath#12345". --> <!-- If your change requires a documentation PR, please link it appropriately. --> ### 📝 Checklist <!-- Put an `x` in all the boxes that apply. --> <!-- If your change requires a documentation PR, please link it appropriately --> <!-- If you're unsure about any of these, don't hesitate to ask. We're here to help! --> <!-- Feel free to remove irrelevant items. --> - [x] The title is concise, informative, and self-explanatory. - [x] The description explains in detail what this PR is about. - [x] I have linked a relevant issue or discussion. - [x] I have created tests covering the changes. - [x] I have updated the documentation accordingly. ### ⌛ Dependencies <!-- List all open PRs that this PR logically depends on - sagemath#12345: short description why this is a dependency - sagemath#34567: ... --> - sagemath#36718 Uses the KL basis implementation <!-- If you're unsure about any of these, don't hesitate to ask. We're here to help! --> URL: sagemath#36790 Reported by: Travis Scrimshaw Reviewer(s): Frédéric Chapoton
<!-- ^^^^^ Please provide a concise, informative and self-explanatory title. Don't put issue numbers in there, do this in the PR body below. For example, instead of "Fixes sagemath#1234" use "Introduce new method to calculate 1+1" --> <!-- Describe your changes here in detail --> We implement the Murphy basis of the symmetric group algebra (as defined by Dipper-James-Mathas) and make this the default cellular basis over positive characteristic since it is (significantly) faster to compute the change of basis necessary. <!-- Why is this change required? What problem does it solve? --> <!-- If this PR resolves an open issue, please link to it here. For example "Fixes sagemath#12345". --> <!-- If your change requires a documentation PR, please link it appropriately. --> ### 📝 Checklist <!-- Put an `x` in all the boxes that apply. --> <!-- If your change requires a documentation PR, please link it appropriately --> <!-- If you're unsure about any of these, don't hesitate to ask. We're here to help! --> <!-- Feel free to remove irrelevant items. --> - [x] The title is concise, informative, and self-explanatory. - [x] The description explains in detail what this PR is about. - [x] I have linked a relevant issue or discussion. - [x] I have created tests covering the changes. - [x] I have updated the documentation accordingly. ### ⌛ Dependencies <!-- List all open PRs that this PR logically depends on - sagemath#12345: short description why this is a dependency - sagemath#34567: ... --> - sagemath#36718 Uses the KL basis implementation <!-- If you're unsure about any of these, don't hesitate to ask. We're here to help! --> URL: sagemath#36790 Reported by: Travis Scrimshaw Reviewer(s): Frédéric Chapoton
<!-- ^^^^^ Please provide a concise, informative and self-explanatory title. Don't put issue numbers in there, do this in the PR body below. For example, instead of "Fixes sagemath#1234" use "Introduce new method to calculate 1+1" --> <!-- Describe your changes here in detail --> We implement the Murphy basis of the symmetric group algebra (as defined by Dipper-James-Mathas) and make this the default cellular basis over positive characteristic since it is (significantly) faster to compute the change of basis necessary. <!-- Why is this change required? What problem does it solve? --> <!-- If this PR resolves an open issue, please link to it here. For example "Fixes sagemath#12345". --> <!-- If your change requires a documentation PR, please link it appropriately. --> ### 📝 Checklist <!-- Put an `x` in all the boxes that apply. --> <!-- If your change requires a documentation PR, please link it appropriately --> <!-- If you're unsure about any of these, don't hesitate to ask. We're here to help! --> <!-- Feel free to remove irrelevant items. --> - [x] The title is concise, informative, and self-explanatory. - [x] The description explains in detail what this PR is about. - [x] I have linked a relevant issue or discussion. - [x] I have created tests covering the changes. - [x] I have updated the documentation accordingly. ### ⌛ Dependencies <!-- List all open PRs that this PR logically depends on - sagemath#12345: short description why this is a dependency - sagemath#34567: ... --> - sagemath#36718 Uses the KL basis implementation <!-- If you're unsure about any of these, don't hesitate to ask. We're here to help! --> URL: sagemath#36790 Reported by: Travis Scrimshaw Reviewer(s): Frédéric Chapoton
<!-- ^^^^^ Please provide a concise, informative and self-explanatory title. Don't put issue numbers in there, do this in the PR body below. For example, instead of "Fixes sagemath#1234" use "Introduce new method to calculate 1+1" --> <!-- Describe your changes here in detail --> We implement the Murphy basis of the symmetric group algebra (as defined by Dipper-James-Mathas) and make this the default cellular basis over positive characteristic since it is (significantly) faster to compute the change of basis necessary. <!-- Why is this change required? What problem does it solve? --> <!-- If this PR resolves an open issue, please link to it here. For example "Fixes sagemath#12345". --> <!-- If your change requires a documentation PR, please link it appropriately. --> ### 📝 Checklist <!-- Put an `x` in all the boxes that apply. --> <!-- If your change requires a documentation PR, please link it appropriately --> <!-- If you're unsure about any of these, don't hesitate to ask. We're here to help! --> <!-- Feel free to remove irrelevant items. --> - [x] The title is concise, informative, and self-explanatory. - [x] The description explains in detail what this PR is about. - [x] I have linked a relevant issue or discussion. - [x] I have created tests covering the changes. - [x] I have updated the documentation accordingly. ### ⌛ Dependencies <!-- List all open PRs that this PR logically depends on - sagemath#12345: short description why this is a dependency - sagemath#34567: ... --> - sagemath#36718 Uses the KL basis implementation <!-- If you're unsure about any of these, don't hesitate to ask. We're here to help! --> URL: sagemath#36790 Reported by: Travis Scrimshaw Reviewer(s): Frédéric Chapoton
Currently the SymmetricGroupAlgebra uses the seminormal basis for computing a cell basis, but this only is guaranteed to work over a field where Maschke's theorem holds. However, it is known that the Kazhdan-Lusztig C' basis at q = 1 for the type A Hecke algebra is a cell basis, We implement that as the fallback when we cannot use the seminormal basis.
We also fix a few typos in the doc that were noticed.
📝 Checklist
⌛ Dependencies