Function: nfhnfmod
Section: number_fields
C-Name: nfhnfmod
Prototype: GGG
Help: nfhnfmod(nf,x,detx): if x=[A,I], and detx is a multiple of the ideal
determinant of x, gives a pseudo-basis of the module sum A_jI_j.
Doc: given a pseudo-matrix $(A,I)$
and an ideal \var{detx} which is contained in (read integral multiple of) the
determinant of $(A,I)$, finds a pseudo-basis in \idx{Hermite normal form}
of the module generated by $(A,I)$. This avoids coefficient explosion.
\var{detx} can be computed using the function \kbd{nfdetint}.