Function: dirdiv
Section: number_theoretical
C-Name: dirdiv
Prototype: GG
Help: dirdiv(x,y): division of the Dirichlet series x by the Dirichlet
 series y.
Doc: $x$ and $y$ being vectors of perhaps different
 lengths but with $y[1]\neq 0$ considered as \idx{Dirichlet series}, computes
 the quotient of $x$ by $y$, again as a vector.
