The Hidden Logic of Sudoku (Second Edition)

Book excerpt: "The Hidden Logic of Sudoku" provides the first systematic perspective of the logical foundations and of the symmetries of the popular game. These are fully exploited to define new resolution rules, new graphical representations and an ordering of the rules consistent with their complexity. The classical pattern of xy-chains has been extended into a homogeneous set of chain rules that, when added to a few elementary rules, suffices to solve almost any puzzle. These rules are illustrated with a hundred puzzles with their full resolution paths. A large collection of puzzles has been processed by Artificial Intelligence (AI) techniques, leading to a precise evaluation of the efficiency of each rule. This pedagogical book is intended for both Sudoku players (who will discover many new facets of the game and new rules - all set in a uniform conceptual framework based on patterns) and teachers or students of Logic or AI (who will appreciate the strict logical foundations).