Function: bnrisconductor
Section: number_fields
C-Name: bnrisconductor0
Prototype: lGDGDG
Help: bnrisconductor(A,{B},{C}): returns 1 if the modulus is the
 conductor of the subfield of the ray class field given by A,B,C (see
 bnrdisc), and 0 otherwise. Slightly faster than bnrconductor if this is the
 only desired result.
Doc: fast variant of \kbd{bnrconductor}$(A,B,C)$; $A$, $B$, $C$ represent
 an extension of the base field, given by class field theory
 (see~\secref{se:CFT}). Outputs 1 if this modulus is the conductor, and 0
 otherwise. This is slightly faster than \kbd{bnrconductor} when the
 character or subgroup is not primitive.
