Opened 2 years ago

Closed 2 years ago

#29698 closed enhancement (fixed)

Implement the cohomology ring of a right-angled Artin group

Reported by: tscrim Owned by:
Priority: major Milestone: sage-9.2
Component: group theory Keywords: cohomology
Cc: Merged in:
Authors: Travis Scrimshaw Reviewers: Frédéric Chapoton
Report Upstream: N/A Work issues:
Branch: 0c4107c (Commits, GitHub, GitLab) Commit: 0c4107c71fa6dc9ffbfd6cfcc6f222a4b4f4d972
Dependencies: Stopgaps:

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Description

Since they have nice structure corresponding to a quotient of an exterior algebra.

Change History (13)

comment:1 Changed 2 years ago by tscrim

  • Branch set to public/groups/raag_cohomology-29698
  • Commit set to f33b09b73c081bd0ced2fc79c9fa7d06570cd325
  • Milestone changed from sage-9.1 to sage-9.2
  • Status changed from new to needs_review

New commits:

​f33b09bImplementation of the cohomology ring of a RAAG.

comment:2 Changed 2 years ago by chapoton

reminds me of #27874

comment:3 Changed 2 years ago by tscrim

It does have the hints of that as the trace monoid is the monoid version of a right-angled Artin group. Although this implementation is quite different IMO.

comment:4 Changed 2 years ago by chapoton

some pyflakes warning, see patchbot reports

comment:5 Changed 2 years ago by git

  • Commit changed from f33b09b73c081bd0ced2fc79c9fa7d06570cd325 to 966ae578679fad8bbd25c12816537b3f21a8c310

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

​abd76f4Merge branch 'public/groups/raag_cohomology-29698' of git://trac.sagemath.org/sage into public/groups/raag_cohomology-29698
​966ae57Fixing pyflakes warnings.

comment:6 Changed 2 years ago by tscrim

Fixed.

comment:7 Changed 2 years ago by chapoton

Do you need to use len in these tests ? 

+        if len(m) == 0:
+            return '1'
+        term = ''
+        for i in m:
+            if len(term) != 0:
+                term += '*'
+            term += 'e' + str(i)
+        return term

comment:8 Changed 2 years ago by git

  • Commit changed from 966ae578679fad8bbd25c12816537b3f21a8c310 to 0c4107c71fa6dc9ffbfd6cfcc6f222a4b4f4d972

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

​0c4107cUsing join and faster bool check in RAAG cohomology.

comment:9 Changed 2 years ago by tscrim

Indeed, I do not. I can also use join() as well.

comment:10 Changed 2 years ago by tscrim

Green patchbot.

comment:11 follow-up: Changed 2 years ago by chapoton

  • Reviewers set to Frédéric Chapoton
  • Status changed from needs_review to positive_review

Looks good. I am just so slightly worried about the pdf doc, but was not able to check that it works. Let me give a positive review nevertheless.

comment:12 in reply to: ↑ 11 Changed 2 years ago by tscrim

Replying to chapoton:

Looks good. I am just so slightly worried about the pdf doc, but was not able to check that it works. Let me give a positive review nevertheless.

Thanks. The pdf doc built for me without any problems.

comment:13 Changed 2 years ago by vbraun

  • Branch changed from public/groups/raag_cohomology-29698 to 0c4107c71fa6dc9ffbfd6cfcc6f222a4b4f4d972
  • Resolution set to fixed
  • Status changed from positive_review to closed
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