Integer polynomials represented by the dense normalized coefficient type
from HexPoly.
10.2. Integer polynomial type
There is no new structure: an integer polynomial is just a normalized
dense polynomial with Int coefficients, so the whole HexPoly API
(constructors, arithmetic, evaluation, Euclidean division over Rat)
is available unchanged. HexPolyZ adds operations as plain functions
in the Hex.ZPoly namespace.