  The Hilbert scheme of n points in the projective plane has a natural
stratification obtained from the associated Hilbert series. In general, the
precise inclusion relation between the closures of the strata is still unknown.
Guerimand studied this problem for strata whose Hilbert series are as close as
possible. Preimposing a certain technical condition he obtained necessary and
sufficient conditions for the incidence of such strata. In this paper we
present a new approach, based on deformation theory, to Guerimand's result.
This allows us to show that the technical condition is not necessary.
