Ground state of interacting spins

The question is posed of how the ground state of the Heisenberg Hamiltonian H= - ΣFij Si-Sj depends on the magnitude s of N interacting spins, particularly in the case of long-ranged oscillatory interactions Fij. It is discussed whether fixing the geometry and the bond strengths Fij suffices to determine the nature of the spin correlations in the ground state, and a review is given of known instances when this is the case; those are special situations in ferromagnetism and antiferromagnetism when qualitative ground-state properties such as "lack of nodes" can be proved to be independent of s.