Self Join Yields Cell Constraints  Match empty cells with filled cells  For each empty cell, one row per filled in value in same row, column or block  Example: Cell 1,1 is empty Cell 2,2 in the same block has a 4 Cannot be 3,4,5,6,7 Bar size 2048 SAS ® and Sudoku SGF 2007, This slide copyright Larry Hoyle, 2007
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