Opened 6 years ago

Closed 5 years ago

#20300 closed defect (fixed)

DirichletGroup should not allow negative modulus

Reported by: wuthrich Owned by:
Priority: trivial Milestone: sage-8.1
Component: number theory Keywords: DirichletGroup
Cc: Merged in:
Authors: Frédéric Chapoton Reviewers: Peter Bruin
Report Upstream: N/A Work issues:
Branch: 3c0f169 (Commits, GitHub, GitLab) Commit: 3c0f169e895f6eafe4d66da0cb5a95a53bec78db
Dependencies: Stopgaps:

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Description 

sage: G = DirichletGroup(-20); G
Group of Dirichlet characters of modulus -20 over Cyclotomic Field of order 4 and degree 2
sage: chi = G.0; chi
Dirichlet character modulo -20 of conductor 4 mapping 11 |--> -1, 17 |--> 1

pretends to work, but then most things like chi.gauss_sum() etc fail.

Either DirichletGroup with a negative modulus should yield an error or return the one with |modulus|

Change History (3)

comment:1 Changed 5 years ago by chapoton

  • Authors set to Frédéric Chapoton
  • Branch set to u/chapoton/20300
  • Commit set to eebac419499666bb61a1af6db969ec974f1684c7
  • Milestone changed from sage-7.2 to sage-8.1
  • Status changed from new to needs_review

done, please review (should be easy)

New commits:

​eebac41trac 20300 no negative modulus for Dirichlet characters

comment:2 Changed 5 years ago by pbruin

  • Branch changed from u/chapoton/20300 to u/pbruin/20300-DirichletGroup_modulus_positive
  • Commit changed from eebac419499666bb61a1af6db969ec974f1684c7 to 3c0f169e895f6eafe4d66da0cb5a95a53bec78db
  • Reviewers set to Peter Bruin
  • Status changed from needs_review to positive_review

I just changed the inequality to modulus <= 0 to make the error message clearer in the case modulus = 0.

comment:3 Changed 5 years ago by vbraun

  • Branch changed from u/pbruin/20300-DirichletGroup_modulus_positive to 3c0f169e895f6eafe4d66da0cb5a95a53bec78db
  • Resolution set to fixed
  • Status changed from positive_review to closed
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