  We study the connection between the dimension of certain spaces of harmonic
functions on a group and its geometric and algebraic properties.
  Our main result shows that (for sufficiently "nice" random walk measures) a
connected, compactly generated, locally compact group has polynomial volume
growth if and only if the space of linear growth harmonic functions has finite
dimension.
  This characterization is interesting in light of the fact that Gromov's
theorem regarding finitely generated groups of polynomial growth does not have
an analog in the connected case. That is, there are examples of connected
groups of polynomial growth that are not nilpotent by compact. Also, the
analogous result for the discrete case has only been established for solvable
groups, and is still open for general finitely generated groups.
