ABSTRACT
A large number of time-dependent problems in physics and engineering are governed by some type of wave equation, which can be in the form of either a scalar or a vector PDE. Typically, boundary conditions must be added to the other initial conditions as a means of ensuring the uniqueness of the solution. Other types of problems, typically of the diusion kind, are governed by PDEs of parabolic types, also requiring an initial condition. Steady state phenomena are usually governed by equations of elliptic type.
