We examine the static and dynamic stability of the solutions of the
Gross-Pitaevskii equation and demonstrate the intimate connection between them.
All salient features related to dynamic stability are reflected systematically
in static properties. We find, for example, the obvious result that static
stability always implies dynamic stability and present a simple explanation of
the fact that dynamic stability can exist even in the presence of static
instability.Comment: 7 pages, 1 figur