Function: rnfidealnormrel
Section: number_fields
C-Name: rnfidealnormrel
Prototype: GG
Help: rnfidealnormrel(rnf,x): relative norm of the ideal x.
Doc: $\var{rnf}$ being a relative
 number field extension $L/K$ as output by \kbd{rnfinit} and $x$ being a
 relative ideal (which can be, as in the absolute case, of many different
 types, including of course elements), computes the relative norm of $x$ as a
 ideal of $K$ in HNF.
