Let $F(x,y)\equiv (F_1(x,y), F_2(x,y))$ be a vector field on $X\times Y$, where $X, Y\subset \mathbb R$.
Let $\operatorname{div}$ denote the divergence operator, i.e., $$\operatorname{div} F = \frac{\partial F_1(x,y)}{\partial x}+ \frac{\partial F_2(x,y)}{\partial y}.$$
Suppose $F$ satisfies the following PDE
\begin{cases} \operatorname{div} F(x,y) = g(x,y), & (x,y)\in X^{\circ}\times Y^{\circ},\\ F(x,y) = m(x,y), & (x,y)\in \partial (X\times Y), \end{cases}
where $g(x,y)$ and $m(x,y)$ are known functions, and $A^{\circ}$ denotes interior of a set $A$ and $\partial A$ denotes the boundary.
What are the different ways to (numerically approximate) solve $F(x,y)$? (When) is the solution unique?