We suggest algorithms for calculating arbitrary order correlation functions (S₁i. . . Sinin)c and distribution functions (Si₁. . . Sinin) of a nonuniform Ising chain.

We consider a proton-glass model with an arbitrary range of competing interactions within two-particle cluster approximation for the free energy and within symmetric replica approach. We show that for the thermodynamic ...

Within the framework of the proposed uni ed proton ordering model for the ferroelectric compounds of the KH₂PO₄ family, in the four-particle cluster approximation for the short-range interactions and mean eld approximation for ...