Function: algdivr
Section: algebras
C-Name: algdivr
Prototype: DGGG
Help: algdivr({al},x,y): element x/y in al (Hamilton quaternions if omitted).
Doc: Given two elements $x$ and $y$ in \var{al} (Hamilton quaternions if
 omitted), returns $xy^{-1}$. Also accepts square matrices with coefficients in
 \var{al}.
