Opened 5 years ago
Closed 5 years ago
#24453 closed defect (fixed)
narrow_class_group: bug report
Reported by:  Kimball Martin  Owned by:  

Priority:  major  Milestone:  sage8.2 
Component:  number fields  Keywords:  narrow class group, quadratic field 
Cc:  Merged in:  
Authors:  Frédéric Chapoton  Reviewers:  Vincent Delecroix 
Report Upstream:  N/A  Work issues:  
Branch:  13f3864 (Commits, GitHub, GitLab)  Commit:  13f3864c0c0932cc2ee24bd49f38fdcb4207d79f 
Dependencies:  Stopgaps: 
Description
The narrow_class_group function does not even work for some simple real quadratic fields. Specifically, while it works for Q(sqrt(2)), it does not for Q(sqrt(3)) (I have not tried other number fields). See snippet below.
sage: version() 'SageMath version 8.1, Release Date: 20171207' sage: F.<a> = QuadraticField(2) sage: F.narrow_class_group() Trivial Abelian group sage: F.<a> = QuadraticField(3) sage: F.narrow_class_group() File "<string>", line 1 [2, [2], [[0, 1]~]] ^ SyntaxError: invalid syntax sage: NumberField(x^23,'a').narrow_class_group() File "<string>", line 1 [2, [2], [[0, 1]~]] ^ SyntaxError: invalid syntax
If it matters, I was using a prebuilt Mac binary.
Change History (6)
comment:1 Changed 5 years ago by
comment:2 Changed 5 years ago by
Authors:  → Frédéric Chapoton 

Branch:  → u/chapoton/24453 
Commit:  → 13f3864c0c0932cc2ee24bd49f38fdcb4207d79f 
Status:  new → needs_review 
New commits:
13f3864  trac 24453 fix narrow class field

comment:4 Changed 5 years ago by
oh, well, I thought it would be a good idea to replace the custom cache by the usual decorator..
comment:5 Changed 5 years ago by
Reviewers:  → Vincent Delecroix 

Status:  needs_review → positive_review 
Oh! I missed the old cache.
comment:6 Changed 5 years ago by
Branch:  u/chapoton/24453 → 13f3864c0c0932cc2ee24bd49f38fdcb4207d79f 

Resolution:  → fixed 
Status:  positive_review → closed 
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Indeed, there is maybe something strange..