Re: Your help needed

[Bill Allombert <allomber@math.u-bordeaux.fr>]

On Thu, Jan 30, 2014 at 07:46:36AM +0900, Kaz Kobara wrote:
> Dear Bill and all,
> 
> > Not unless you know the factorisation of the order of the elliptic curve,
> > or some similar useful information
> 
> Thank you for this information.
> 
> That's why the manual of ellorder() 
> http://pari.math.u-bordeaux.fr/dochtml/html/Functions_related_to_elliptic_cu
> rves.html
> suggests to supply o of
> 
> ? N = p+1-ellap(E,p); o = [N, factor(N)];
> 
> This solved our problem. Thank you very much.

By curiosity, how did you compute factor(N) ?

Cheers,
Bill.