Re: class number of biquadratic number field

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

On Sun, Sep 17, 2006 at 04:49:43PM +0800, Cheng Xiaoyun wrote:
> When I use rnfinit to compute the class number of biquadratic number field,
> I can not get the result. When I write the following:
> ? x;y;
> ? f=y^2-3
> ? e=bnfinit(f)
> ? y=Mod(y,f)
> ? g=x^2-2
> ? e=rnfinit(e,g)
> ? e.clgp
> 
> I only get "incorrect type in .clgp" .  I think that the class group can
> only be given for big number fields. But how can I get big number field for
> relative number fields.

There is no rnfbnfinit(), but you can do

bnfinit(rnfequation(f,g))
or
e=nfinit(f);
e=rnfinit(e,g);
bnfinit(e.pol)

Cheers
Bill.