e/Discrete Poisson equation

Information
has gloss	eng: In mathematics, the Discrete Poisson Equation is the finite difference analog of the Poisson equation. In it, the discrete Laplace operator takes the place of the Laplace operator. The discrete Poisson equation is frequently used in numerical analysis as a stand-in for the continuous Poisson equation, although it is also studied in its own right as a topic in discrete mathematics.
lexicalization	eng: Discrete Poisson equation
instance of	e/Finite difference