relative basis for Z_L over Z_K

[Markus Endres <me@mendres.org>]

hi

I guess it's not very difficult but I don't know how to do that.

let L|K|Q a tower of fields given by nfinit() or bnfinit(). now, one can
compute an integral basis for Z_L and Z_K with L.zk resp. K.zk. 

but both are expressed on the powers of alpha resp. theta, when
K=Q(theta), L=K(alpha). that means, that the basis is given over Q, the
rationals. 

what I need ist the basis of Z_L expressed over Z_K.

hope somebody can help me

thx in advance

greetings 

markus