I am starting out with cryptanalysis, and one of the problems is defined as:
In this problem, we consider the case of a single bivariate homogeneous equation,i.e., an equationF(x,y) = 0 of degree D where F is of the form: $$F(x,y) = \sum_{i=0}^{D} F_ix^iy^{D-i}$$
I can see that $x^iy^{D-1}$ in the summation stands for degree $D$ polynomial, but I don't get what $F_i$ is for. The question is in the context of bivariate homogeneous equations in prime files/ integer ring.