The Ground State of a Two-dimensional Lattice System with a Long-range   Interparticle Repulsion. Effective Lowering of Dimension
  It has been shown that effective lowering of dimension underlies ground-state space structure and properties of two-dimensional lattice systems with a long-range interparticle repulsion. On the basis of this fact a rigorous general procedure has been developed to describe the ground state of the systems. 
A.A.Slutskin, V.V.Slavin, and H. A. Kovtun (Institute for Low   Temperature Physics and Engineering, Kharkov, Ukraine)