Changes between Version 4 and Version 7 of Ticket #7729


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Timestamp:
Dec 19, 2009, 12:23:57 AM (13 years ago)
Author:
Daniel Bump
Comment:

I've revised it so that it works with affine Weyl groups.

I don't mind renaming it IwahoriHeckeAlgebraT but it seems to me that perhaps other presentations can be handled within this framework. I think I should leave the refactoring to the category framework to you.

I will make the algebra generators into a family. When I've done that I will change the status back to needs review.

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  • Ticket #7729

    • Property Status changed from new to needs_work
    • Property Component changed from algebra to combinatorics

  • Ticket #7729 – Description

    v4 v7  
    99}}}
    1010
    11 This code is very tested for type A and is almost certainly correct for Weyl groups of finite type. I have not tried it for any affine Weyl groups.
     11This code is very tested for type A and is almost certainly correct for Weyl groups of finite type. It also works for affine Weyl groups in the most recently posted version.
    1212
    1313The following issues remain.
    1414
    1515* David Roe suggested that the _coerce_impl method should be removed. I have not looked at this yet.
    16 
    17 * It should be made to work with Affine Weyl groups. I have not checked whether this requires further modification.
    1816
    1917* Subjectively, it seems a little slow compared with a previous implementation for type A only. This is probably a limitation of the {{{WeylGroup()}}} class on which it depends. My earlier implementation was based on Permutation. If it proves unacceptably slow it may be possible to speed it up by a caching scheme.
    … …  
    2321For some further discussion of this topic see
    2422http://groups.google.com/group/sage-combinat-devel/browse_thread/thread/78fc23f23cafe705?hl=en
    25 
    26 It is well tested for type A and is probably correct for all Cartan Types of finite type.