Our treatment of rational surfaces will parallel rather closely the
treatment of rational curves. Unlike rational curves, there is only
one natural way to polarize a rational surface. However, since a rational
surface can be viewed as the projection of a polynomial surface, and
there are two ways of polarizing a polynomial surface, there are two
ways to specify a rational surface in terms of control points. Definition:
We can define a rational surface of degree m by the following expression:
where we deal with which is the set of polynomials of degree at most
m such that at least one of the pi has degree m.