Editing Potential theory (section)

==Local behavior==
An important topic in potential theory is the study of the local behavior of harmonic functions. Perhaps the most fundamental theorem about local behavior is the regularity theorem for Laplace's equation, which states that harmonic functions are analytic. There are results which describe the local structure of [[level set]]s of harmonic functions. There is [[Bôcher's theorem]], which characterizes the behavior of [[Isolated singularity|isolated singularities]] of positive harmonic functions. As alluded to in the last section, one can classify the isolated singularities of harmonic functions as removable singularities, poles, and essential singularities.