Editing Harmonic function (section)

===Harmonic forms===
One generalization of the study of harmonic functions is the study of [[harmonic form]]s on [[Riemannian manifold]]s, and it is related to the study of [[cohomology]]. Also, it is possible to define harmonic vector-valued functions, or harmonic maps of two Riemannian manifolds, which are critical points of a generalized Dirichlet energy functional (this includes harmonic functions as a special case, a result known as  [[Dirichlet principle]]). This kind of harmonic map appears in the theory of minimal surfaces. For example, a curve, that is, a map from an interval in {{tmath|\R}} to a Riemannian manifold, is a harmonic map if and only if it is a [[geodesic]].