Journal of Physics A Mathematical and General
A special series expansion technique for the square lattice
Ian Graham Enting, R. J. Baxter
Abstract
The partition functions of generalised Ising-type models on the square lattice can be approximated in terms of the partition functions for finite n*n, n*(n-1) and (n-1)*(n-1) lattices. When expressed as high-temperature series, these approximations give terms through to order 2n or 2n+1 correctly.