Key points are not available for this paper at this time.
It is shown that there is a class of graphs of the Ising model (or (Heisenberg model for T>T₂ₔₑ₈₄) which is comprised of cycle graphs plus some excluded volume effects which sum to the spherical model. The spherical model, suitably generalized for T<T₂ₔₑ₈₄, was conjectured in a previous work to be the high-density limit of the Ising model, correct to 1z, where z is the number of spins in the range of the exchange potential (not restricted to nearest neighbor interactions). z^1{3} measures the range of the exchange potential. This is now proved by examining the omitted graphs. The error is shown to be O (1{z^2}).
R. Brout (Sat,) studied this question.