Complex sentence: In potential theory, the Poisson kernel is an integral kernel, the derivative of the Green's function for the two-dimensional Laplace equation, under circular symmetry, using Dirichlet boundary conditions.
Split into simpler sentences: In potential theory, the Poisson kernel is an integral kernel, used for solving the two-dimensional Dirichlet problem. Specifically, it is the derivative of the Green's function for the two-dimensional Laplace equation, under circular symmetry, using Dirichlet boundary conditions.