I am familiar with polynomials, for example, f1(x) = a0 x0 + a1 x1 + a2 x2 + a3 x3 + ...
where the ai are constant coefficients.
But now I am wondering what the correct terminology is for an equation with mixed terms.
For example, say you have a function of two variables f(x, y), three variables f(x, y, z), or more. Something like the following:
f2(x,y) = a0 x0 + a1 xy + a2 x2y + a3 x3y + a4 xy4 + a5 x2 y2
Basically, the equation is comprised of a bunch of mixed terms, but no transcendentals.
Does this sort of equation have a name when it is being discussed?