A polynomial-growth harmonic function of order at most on a complete Riemannian
manifold is a harmonic function
for which
for a fixed base point and some finite constant
. Let
be the dimension of this
vector space. On Euclidean
space
, these are precisely the harmonic
polynomials of degree at most
for a nonnegative integer
, giving
where the second term is zero for .
In dimension three this is
. The harmonic
dimension comparison conjecture concerns these dimensions under nonnegative Ricci curvature.