Re: Traces of finite fields elements lifted to integers

[Karim Belabas <Karim.Belabas@math.u-bordeaux.fr>]

* Emmanuel ROYER, LMBP [2019-08-17 06:09]:
> Hello!
> 
> I would like to compute traces of finite fields elements.
> 
> Let us take F_8 as an example.
> 
> The following is obviously false but I am not able to see why. Is not conjvec(z^4) supposed to have 3 elements?
> 
> ? T=ffinit(2,3);
> ? t=ffgen(T,'t);
> ? z=ffprimroot(t);
> ? F8=concat([0],[z^d | d <- [1..7]]);
> ? tr(h)=vecsum(conjvec(h));
> ? apply(tr,F8)
> %7 = [0, t + 1, t^2 + 1, t^2 + 1, t^2 + t, t + 1, t^2 + t, 0]

Hi Emmanuel,

  Yes, this is wrong. The typo is now fixed in 'master'.

Thanks for your report !

    K.B.

P.S. apply(trace, F8) works directly (and should be much faster).
--
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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