"University of Notre Dame complex networks researcher Zoltan Toroczkai and Notre Dame postdoctoral researcher Maria Ercsey-Ravasz (...) can not only explain why some Sudoku puzzles are harder than others, they have also developed a mathematical algorithm that solves Sudoku puzzles very quickly, without any guessing or backtracking." http://newsinfo.nd.edu/news/32826-notre-dame-researcher-helps-make-sudoku-pu zzles-less-puzzling/ Main paper: www.nature.com/srep/2012/121011/srep00725/full/srep00725.html Christian.