Susceptibility of the checkerboard Ising model

Abstract
The authors show that at the disorder variety, the n-point correlation functions of the checkerboard Potts model have a simple causal structure, and decay as simple exponentials for space-like separations. An exact expression for the susceptibility in the Ising case is obtained. The result is additional evidence in favour of the conjectured S4 symmetry of the checkerboard Potts model in the presence of a finite field.