Hello

May I dare ask : is it possible that there is a problem in formula (0.2) of 
Gross-Zagier ? I do not manage to make sense of the powers of pi and 2.

As far as I can see, there should be 4 gamma factors (0,0,1,1), weight 2, 
and the conductor should be N**2 *  D**2

But there are some spurious 2 and pi factors. As it is this does not fit 
into Dokchister setting..

Frederic

Le mercredi 13 mai 2015 10:06:43 UTC+2, [email protected] a écrit :
>
> Hello,
>
> thanks a lot. I was suspecting something like that. I have to look at the 
> code now.
>
> And indeed, "Gross-Zagier L-functions" does not seem to be a standard name 
> for these L-functions.
>
> Frederic
>
> Le mardi 12 mai 2015 17:17:10 UTC+2, chris wuthrich a écrit :
>>
>> Hi Frederic,
>>
>> I believe that the name Gross-Zagier L-function is not standard. At least 
>> I had to go and look in the code to find out what its definition is. So the 
>> documentation should probably include a description of the definition.
>>
>> Now to your question: The function is L_A(E,s) depending on an elliptic 
>> curve E/Q and an ideal class A in an imaginary quadratic field. The 
>> functional equation for it is (0.2) on page 267 of Gross-Zagier. 
>> You are asking what value of "conductor" you have to feed Dokchitser's 
>> implementation. Comparing the two and making sure the same normalisations 
>> are used, one should be able to get the answer. If I did it right, I get 
>> that the value is N^2 |D|^2/4 where N is the conductor of the elliptic 
>> curve and D is the discriminant of the quadratic field. (which may be 4*d). 
>> But I may be wrong. (I am actually surprised it is independend of A.)
>>
>>  In any case, the function check_functional_equation should tell you if 
>> you got it right. 
>>
>> Chris
>>  
>>
>> On 12 May 2015 at 14:15, <[email protected]> wrote:
>>
>>> Hello again,
>>>
>>> well, in fact what should be the correct conductor (level ?) in full 
>>> generality is not clear to me at all. So an expert help is really required !
>>>
>>> input : An elliptic curve of conductor N, and the imaginary number field 
>>> Q(\sqrt(-d))
>>>
>>> wanted: a formula involving N and d for the "conductor" for the 
>>> Gross-Zagier L-function attached to the input. Could it be just always 
>>> N*N*d*d ? or sometimes N*N*d*d/4 ?
>>>
>>> Should I ask that in MathOverflow ?
>>>
>>> Frederic
>>>
>>> Le samedi 2 mai 2015 20:24:51 UTC+2, [email protected] a écrit :
>>>>
>>>> Hello,
>>>>
>>>> I think I managed to find the problem myself. The conductor was divided 
>>>> by 4 for no special reason..
>>>> So this is now working. If somebody is interested to test..
>>>>
>>>> Frédéric
>>>>
>>>> Le samedi 2 mai 2015 18:30:55 UTC+2, [email protected] a écrit :
>>>>>
>>>>> Dear number theorists,
>>>>>
>>>>> To avoid thinking about some other things, I have been fighting with 
>>>>> ticket #4606, dealing with "Gross-Zagier L-function" attached to a pair 
>>>>> (E,A) where
>>>>> E is an elliptic curve over Q and A an ideal class in a quadratic 
>>>>> (imaginary?) number field.
>>>>>
>>>>> I am now in the state where the Dirichlet coefficients of the wanted 
>>>>> L-function are computed correctly, but still the numerical answer is 
>>>>> wrong.
>>>>> So I was wondering if maybe the parameters given to Dokchister may be 
>>>>> wrong.
>>>>> If somebody here could help, that would be great ! Or maybe forward 
>>>>> this question to somebody knowing the answer?
>>>>>
>>>>> http://trac.sagemath.org/ticket/4606
>>>>>
>>>>> The parameters are in the file src/sage/modular/modform/l_series.py
>>>>>
>>>>> thanks a lot,
>>>>>
>>>>> Frédéric
>>>>>
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>>
>>

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