Opened 18 months ago

Closed 4 months ago

#14095 closed defect (fixed)

SymmetricGroup as a proper WeylGroup

Reported by: nthiery Owned by: sage-combinat
Priority: major Milestone: sage-6.2
Component: combinatorics Keywords: days45, coxeter
Cc: tscrim Merged in:
Authors: Frédéric Chapoton Reviewers: Travis Scrimshaw
Report Upstream: N/A Work issues:
Branch: b790a37 (Commits) Commit: b790a3788bfeda6e2f685fbf3be5b01d21dd9680
Dependencies: Stopgaps:

Description

During Sara Billey's talk, it came up that not all of the Weyl group functionalities are available for the symmetric group:

  • The symmetric group does not implement CartanType?
  • The Stanley symmetric function code uses the old fashionned W.unit() rather than W.one(). There might be some other occurences that should be cleaned up

Test case:

sage: G = SymmetricGroup(4)
sage: w = G.from_reduced_word([3,2,3,1])
sage: w.stanley_symmetric_function()
3*m[1, 1, 1, 1] + 2*m[2, 1, 1] + m[2, 2] + m[3, 1]

Change History (14)

comment:1 Changed 12 months ago by jdemeyer

  • Milestone changed from sage-5.11 to sage-5.12

comment:2 Changed 7 months ago by tscrim

  • Cc tscrim added

comment:3 Changed 6 months ago by vbraun_spam

  • Milestone changed from sage-6.1 to sage-6.2

comment:4 Changed 4 months ago by chapoton

  • Authors set to Frédéric Chapoton
  • Branch set to u/chapoton/14095
  • Commit set to c97072a455237563dea59c12bfb071dc9b355b7e
  • Keywords coxeter added
  • Status changed from new to needs_review

Here is a git branch that

1) introduces the cartan_type method in SymmetricGroup

2) transforms a few W.unit() into W.one()


New commits:

c97072atrac #14095 remove use of .unit ; added cartan_type for SymmetricGroup

comment:5 Changed 4 months ago by tscrim

FYI - On my TODO list to review.

comment:6 Changed 4 months ago by tscrim

  • Branch changed from u/chapoton/14095 to u/tscrim/14095
  • Commit changed from c97072a455237563dea59c12bfb071dc9b355b7e to 3f77996aca99c269302db147dc4826cc51e8a5bf
  • Reviewers set to Travis Scrimshaw

Looks good overall. I've caught one more unit in the category AffineWeylGroups. I've also marked some tests as # long time in permgroup_named.py since basic testing of that file was taking forever. Plus I've done some other tweaks to that file (gawd that file needs cleanup though). So if you're happy with my changes then positive review.


New commits:

4df5a62One more unit() to one().
3f77996Some misc cleanup to permgroup_named.py.

comment:7 Changed 4 months ago by chapoton

Looks good to me. But maybe one should add the "test case" in the ticket description somewhere ?

comment:8 Changed 4 months ago by chapoton

  • Branch changed from u/tscrim/14095 to u/chapoton/14095
  • Commit changed from 3f77996aca99c269302db147dc4826cc51e8a5bf to 849583956d1fc8e111a7a1d977d79f772872a179

I have added a doctest and taken the opportunity to correct the reference section. I agree with your previous changes. If you agree with mines, please set to positive review.


New commits:

8495839trac #14095 added the new example from the trac ticket

comment:9 Changed 4 months ago by git

  • Commit changed from 849583956d1fc8e111a7a1d977d79f772872a179 to 5f088582bc60c9030acc766009d2092d37c44089

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

5f08858correct formatting of doc and raise syntax for python3

comment:10 Changed 4 months ago by git

  • Commit changed from 5f088582bc60c9030acc766009d2092d37c44089 to 1573f6b7e5577a4e60a54f7afd85aa5c09ea5cad

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

1573f6bmore doc correction

comment:11 Changed 4 months ago by tscrim

Could you also change that \dots into \cdots? With that, you can set positive review on my behalf. Thanks Frederic.

comment:12 Changed 4 months ago by git

  • Commit changed from 1573f6b7e5577a4e60a54f7afd85aa5c09ea5cad to b790a3788bfeda6e2f685fbf3be5b01d21dd9680

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

b790a37trac #14095 cdots instead of dots

comment:13 Changed 4 months ago by chapoton

  • Status changed from needs_review to positive_review

Done.

comment:14 Changed 4 months ago by vbraun

  • Branch changed from u/chapoton/14095 to b790a3788bfeda6e2f685fbf3be5b01d21dd9680
  • Resolution set to fixed
  • Status changed from positive_review to closed
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