Opened 8 years ago
Closed 8 years ago
#15505 closed defect (fixed)
Braid Group construction misses some relations
Reported by: | mmarco | Owned by: | |
---|---|---|---|
Priority: | major | Milestone: | sage-5.13 |
Component: | group theory | Keywords: | braid groups |
Cc: | vbraun, ncohen, chapoton | Merged in: | sage-5.13.rc0 |
Authors: | Miguel Marco | Reviewers: | Travis Scrimshaw |
Report Upstream: | N/A | Work issues: | |
Branch: | Commit: | ||
Dependencies: | Stopgaps: |
Description
Braid Groups are constructed over a finitely presented group, but not all relations are present:
sage: B=BraidGroup('a,b,c') sage: B Braid group on 4 strands sage: B.relations() (a*b*a*b^-1*a^-1*b^-1,)
Attachments (1)
Change History (7)
comment:1 Changed 8 years ago by
- Status changed from new to needs_review
comment:2 Changed 8 years ago by
Version 0, edited 8 years ago
by
(next)
comment:3 Changed 8 years ago by
You are right. Here is a new patch.
comment:4 Changed 8 years ago by
- Reviewers set to Travis Scrimshaw
Could you add a proper commit message? Once that's done, you can set this to positive review on my behalf. Thanks!
Changed 8 years ago by
comment:5 Changed 8 years ago by
- Status changed from needs_review to positive_review
comment:6 Changed 8 years ago by
- Merged in set to sage-5.13.rc0
- Resolution set to fixed
- Status changed from positive_review to closed
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The if statement is always true since
range(a, b)
is[a, a+1, ..., b-2, b-1]
(or you can think of it as the integer points in th internal[a, b)
). So I think this should work: