Key points are not available for this paper at this time.
For pt.I see Commun. Phys., vol.2, p.115 (1977). Presents numerical results for the ground-state properties of the simplest system showing the frustration effect, Ising spins on a square lattice with a variable concentration x of antiferromagnetic interactions. Ferromagnetism disappears at a concentration xc approximately 0.09. The ground-state energy and degeneracy have markedly different behaviours below and above xc. The authors compare the results with other calculations and stress the advantages of the frustration approach.
Vannimenus et al. (Wed,) studied this question.