3D-consistency 1 3d-consistency 1 Backlund transformations 1 Bäcklund transformations 1 Classification (of information) 1 Consistency property Darboux transformations 1 Difference equations 1 Integrable lattice equation 1 Integrable lattice equations 1 Lattice equation 1 Mathematical transformations 1 Nonlinear equations 1 Partial difference equations 1 Quad-graph 1 Quad-graph equation 1 Quad-graph equations 1 Soliton solutions 1 Solitons 1