We define the characteristic
function for each harmonic function having prescribed singularities in a locally
Euclidean space and the class of harmonic functions with bounded characteristic. The
main result is that any harmonic function of bounded characteristic can be
represented as the difference of two positive harmonic functions with prescribed
singularities. Thus the well-known theory of the characteristic functions associated
with meromorphic functions has an analogue for harmonic functions in locally
Euclidean spaces.