Abstract: The ground state of the Heisenberg-Diracova-Van Vleck ferromagnetic Hamiltonian for a system of a finite number of spin 1/2 particles results from rotations and superpositions from the state in which all the spins are oriented the same way. A rigorous of this folklore statement will be presented which is independent of dimension and topology of the lattice. For more details see J. Dittrich and V. Inozemtsev, math-ph/0012048.