Re: Error in |p=3;elldivpol(ellinit(Mod(1,p)*[0,0,0,0,1]),4)|

Bill Allombert <[email protected]> Thu, 27 Jun 2024 10:59:17 +0200
Newsgroups gmane.comp.mathematics.pari.devel
Message-ID <Zn0p5WVSBYsM--fl@seventeen>
On Thu, Jun 27, 2024 at 11:34:34AM +0300, Georgi Guninski wrote:
> ? p=13;elldivpol(ellinit(Mod(1,p)*[0,0,0,0,1]),4)
> %149 = Mod(8, 13)*x^9 + Mod(12, 13)*x^6 + Mod(5, 13)*x^3 + Mod(1, 13)
> ? p=3;elldivpol(ellinit(Mod(1,p)*[0,0,0,0,1]),4)
>   ***   at top-level: p=3;elldivpol(ellinit(Mod(1,p)*[0,0,0,0,1]),4)
>   ***                     ^------------------------------------------
>   *** elldivpol: incorrect type in checkell (t_VEC).

The curve y^2 = x^3 +1 is singular modulo 3, so this is not an elliptic curve,
so this is an invalid input.

Cheers,
Bill