Some of our readers will recall the fiendishly difficult particle physics Sudoku puzzle I created for the June/July 2007 issue of symmetry.
As Sudoku has taken off in popularity, a new area of mathematics has grown: Sudoku mathematics! There are many open math questions to do with Sudoku, especially when you generalize a Sudoku beyond the usual 9x9 grid. Combinatorics, number theory, and group theory all come into play.
One open question is how many clue entries you need to make a Sudoku solvable. There are Sudoku puzzles with only 17 clues, but can that be lowered? A new distributed computing challenge seeks to provide an answer.
International Science Grid This Week recently ran a cool story about the challenge. As for the particle physics Sudoku, if you need help, here's the solution.
