Opened 2 years ago

Closed 2 years ago

#24030 closed defect (fixed)

Weight 1 Eisenstein series for GammaH groups

Reported by: davidloeffler Owned by:
Priority: major Milestone: sage-8.1
Component: modular forms Keywords:
Cc: Merged in:
Authors: David Loeffler Reviewers: David Roe
Report Upstream: N/A Work issues:
Branch: eb3d59d (Commits) Commit: eb3d59da771109ba0033fc67d0f4e539455f7ca3
Dependencies: Stopgaps:

Description

Cusp forms of weight 1 are hard, but Eisenstein forms are not especially harder in weight 1 than in any other weight, and all our Eisenstein functionality is supposed to work fine with weight 1. However, something funny happens with GammaH levels:

ModularForms(Gamma1(9), 1).dimension() # works
4 
ModularForms(GammaH(9, [4]), 1).dimension() # boom
---------------------------------------------------------------------------
NotImplementedError                       Traceback (most recent call last)
<ipython-input-39-bb052dceb2b6> in <module>()
----> 1 ModularForms(GammaH(Integer(9), [Integer(4)]), Integer(1)).dimension()

/usr/local/sage/sage-1/local/lib/python2.7/site-packages/sage/modular/modform/ambient.pyc in dimension(self)
    207             return self.__dimension
    208         except AttributeError:
--> 209             self.__dimension = self._dim_eisenstein() + self._dim_cuspidal()
    210             return self.__dimension
    211 

/usr/local/sage/sage-1/local/lib/python2.7/site-packages/sage/modular/modform/ambient.pyc in _dim_eisenstein(self)
    650         except AttributeError:
    651             if self.weight() == 1:
--> 652                 self.__the_dim_eisenstein = len(self.eisenstein_params())
    653             else:
    654                 if arithgroup.is_Gamma1(self.group()) and self.character() is not None:

/usr/local/sage/sage-1/local/lib/python2.7/site-packages/sage/modular/modform/ambient.pyc in eisenstein_params(self)
    731                     eps = self.level()
    732                 else:
--> 733                     raise NotImplementedError
    734             params = eis_series.compute_eisenstein_params(eps, self.weight())
    735             self.__eisenstein_params = Sequence(params, immutable=True)

NotImplementedError: 

Change History (4)

comment:1 Changed 2 years ago by davidloeffler

  • Branch set to public/24030-weight1

comment:2 Changed 2 years ago by davidloeffler

  • Authors set to David Loeffler
  • Commit set to eb3d59da771109ba0033fc67d0f4e539455f7ca3
  • Status changed from new to needs_review

Here's a tiny little fix


New commits:

004d129Trac 24030: fixes to weight 1 modular forms
eb3d59dSlight tweak to allow more cases of weight 1 mod forms spaces with character

comment:3 Changed 2 years ago by roed

  • Reviewers set to David Roe
  • Status changed from needs_review to positive_review

Looks fine to me.

comment:4 Changed 2 years ago by vbraun

  • Branch changed from public/24030-weight1 to eb3d59da771109ba0033fc67d0f4e539455f7ca3
  • Resolution set to fixed
  • Status changed from positive_review to closed
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