Changes between Version 7 and Version 9 of Ticket #7729


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Timestamp:
Jan 2, 2010, 10:59:58 PM (13 years ago)
Author:
Daniel Bump
Comment:

I posted a revised version. With this version, the base ring can be either a field containing q1 and q2, or a LaurentPolynomialRing?. The previous version did not work with LaurentPolynomialRings?.

Also, methods were added to compute inverses of basis elements, a common task.

Finally, there is a bug fix in sage.categories.pushout (import PolynomialRing? when needed).

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  • Ticket #7729

    • Property Status changed from needs_work to needs_review

  • Ticket #7729 – Description

    v7 v9  
    99}}}
    1010
    11 This 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.
    12 
    13 The following issues remain.
    14 
    15 * David Roe suggested that the _coerce_impl method should be removed. I have not looked at this yet.
    16 
    17 * 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.
    18 
    19 * Later I may add a method to compute intertwining elements which depend on spectral parameters. These have applications to representations of p-adic 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.
    2012
    2113For some further discussion of this topic see