In mathematics, a Cauchy boundary condition augments an ordinary differential equation or a partial differential equation with conditions that the solution must satisfy on the boundary; ideally so as to ensure that a unique solution exists.

In mathematics, the Neumann (or second-type) boundary condition is a type of boundary condition, named after Carl Neumann.

In mathematics, the Dirichlet boundary condition is imposed on an ordinary or partial differential equation, such that the values that the solution takes along the boundary of the domain are fixed.

In mathematics, the Robin boundary condition, or third type boundary condition, is a type of boundary condition, named after Victor Gustave Robin.