Karim Belabas on Tue, 16 Feb 2021 14:08:30 +0100


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Re: New GP function ellrank (2-descent) 

* Bill Allombert [2021-02-16 13:51]:
> > Also what does the output of ellrankinint() contain?   (If you say
> > that it is very technical and I should not worry about it, I will feel
> > like a Mathematica user!)   In particular, does it contain the
> > quartics which represent elements of (or generators of) the 2-Selmer
> > group?
> 
> No, it only contains the bnfinit of the 2-division polynomial.
> This way you can also use it for twists.

More precisely the "bnfinit" for the étale Q-algebra Q[X] / (P), where
P is the 2-division polynomial.

Cheers,

    K.B.
--
Karim Belabas, IMB (UMR 5251)  Tel: (+33) (0)5 40 00 26 17
Universite de Bordeaux         Fax: (+33) (0)5 40 00 21 23
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