Pfaffian Correlation Functions of Planar Dimer Covers
  The Pfaffian structure of the boundary monomer correlation functions in the dimer-covering planar graph models is rederived through a combinatorial / topological argument. These functions are then extended into a larger family of order-disorder correlation functions which are shown to exhibit Pfaffian structure throughout the bulk. Key tools involve combinatorial switching symmetries which are identified through the loop-gas representation of the double dimer model, and topological implications of planarity. 
Michael Aizenman and Manuel La\'inz Valc\'azar and Simone Warzel
math-ph cond-mat.stat-mech math.MP