Opened 15 months ago

Closed 7 months ago

#15201 closed defect (fixed)

Problem with Hecke eigenvalues with the same index as the level

Reported by: fstromberg Owned by:
Priority: major Milestone: sage-6.2
Component: modular forms Keywords:
Cc: Merged in:
Authors: Alex Ghitza Reviewers: Peter Bruin
Report Upstream: N/A Work issues:
Branch: 56341a3 (Commits) Commit: 56341a3580c8f63a7e5b32e34325e23b021efc99
Dependencies: Stopgaps:

Description (last modified by AlexGhitza)

It seems to be a problem to compute Hecke eigenvalues for Modular Symbol subspaces at integers dividing the level N unless the eigenvalue for the Hecke operator at N is computed first.
I have verified this problem for sage versions between 5.8 and 5.12.beta.

Example

sage: M=ModularSymbols(5,6,sign=1)
sage: S=M.decomposition()
sage: f=S[0]
sage: f.eigenvalue(10)
IndexError                                Traceback (most recent call last)
...
IndexError: n must be a positive integer
sage: f.eigenvalue(5)
25
sage: f.eigenvalue(10)
50

Change History (7)

comment:1 Changed 10 months ago by vbraun_spam

  • Milestone changed from sage-6.1 to sage-6.2

comment:2 Changed 7 months ago by AlexGhitza

  • Description modified (diff)

comment:3 Changed 7 months ago by AlexGhitza

The code used the recursive formula for the Hecke eigenvalues of p-power index without implementing the base case. This is fixed in the attached branch.

comment:4 Changed 7 months ago by AlexGhitza

  • Branch set to u/AlexGhitza/ticket/15201
  • Created changed from 09/15/13 17:00:39 to 09/15/13 17:00:39
  • Modified changed from 04/24/14 07:02:50 to 04/24/14 07:02:50

comment:5 Changed 7 months ago by AlexGhitza

  • Authors set to Alex Ghitza
  • Commit set to 56341a3580c8f63a7e5b32e34325e23b021efc99
  • Status changed from new to needs_review

New commits:

56341a3fix Hecke eigenvalues recurrence

comment:6 Changed 7 months ago by pbruin

  • Component changed from number theory to modular forms
  • Reviewers set to Peter Bruin
  • Status changed from needs_review to positive_review

comment:7 Changed 7 months ago by vbraun

  • Branch changed from u/AlexGhitza/ticket/15201 to 56341a3580c8f63a7e5b32e34325e23b021efc99
  • Resolution set to fixed
  • Status changed from positive_review to closed
Note: See TracTickets for help on using tickets.