Opened 8 years ago
Closed 6 years ago
#14196 closed defect (fixed)
"subgroups" fails for C1 x C2
Reported by:  mstreng  Owned by:  malb 

Priority:  major  Milestone:  sage6.4 
Component:  group theory  Keywords:  abelian group subgroups invfac one 
Cc:  bisson  Merged in:  
Authors:  Travis Scrimshaw  Reviewers:  Frédéric Chapoton 
Report Upstream:  N/A  Work issues:  
Branch:  1b92c39 (Commits)  Commit:  1b92c39c04fd82fd3769abbd8059e7dda0de865b 
Dependencies:  Stopgaps: 
Description
In Sage 5.7:
sage: A = AbelianGroup([2,1]) sage: A Multiplicative Abelian group isomorphic to C2 x C1 sage: A.subgroups() [Multiplicative Abelian subgroup isomorphic to C2 generated by {f0}, Trivial Abelian subgroup] sage: B = AbelianGroup([1,2]) sage: B Multiplicative Abelian group isomorphic to C1 x C2 sage: B.subgroups() Vectors not LI: [[0, 0], [0, 1]] ... ValueError: The given basis vectors must be linearly independent.
This last command should work just as well as A.subgroups().
Change History (13)
comment:1 Changed 8 years ago by
comment:2 Changed 8 years ago by
 Cc bisson added
comment:3 Changed 7 years ago by
 Milestone changed from sage5.11 to sage5.12
comment:4 Changed 7 years ago by
 Milestone changed from sage6.1 to sage6.2
comment:5 Changed 7 years ago by
 Milestone changed from sage6.2 to sage6.3
comment:6 Changed 6 years ago by
 Milestone changed from sage6.3 to sage6.4
comment:7 Changed 6 years ago by
 Branch set to public/groups/fix_subgroups14196
 Commit set to 1b92c39c04fd82fd3769abbd8059e7dda0de865b
 Component changed from commutative algebra to group theory
 Status changed from new to needs_review
New commits:
1b92c39  Fix for subgroups of abelian groups whose first part is a trivial group.

comment:8 Changed 6 years ago by
Is it me or is this commit in Sage already ?
Nathann
comment:9 Changed 6 years ago by
It seems to be me. And the trac server which seems to say that the diff between this branch and Sage is empty O_o
comment:10 Changed 6 years ago by
I think it's a trac bug that pops up sporadically.
comment:11 Changed 6 years ago by
 Reviewers set to Frédéric Chapoton
 Status changed from needs_review to positive_review
ok, lgtm
comment:12 Changed 6 years ago by
Thanks Frederic.
comment:13 Changed 6 years ago by
 Branch changed from public/groups/fix_subgroups14196 to 1b92c39c04fd82fd3769abbd8059e7dda0de865b
 Resolution set to fixed
 Status changed from positive_review to closed
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In Sage 5.6, it was still:
I think the situation in Sage 5.7 is an improvement, except of course for the failure to compute
B.subgroups()
.