If you pick up a Sudoku puzzle with your morning coffee, you may want to count the number of clues before you begin. An Irish mathematician has recently proven that Sudoku puzzles with 16 clues or less do not have unique solutions. Sudoku fans and mathematicians have long suspected that designing a puzzle with 16 clues was impossible. Using a supercomputing facility, Gary McGuire was able to prove it. Unfortunately, if you’re struggling with a more forgiving puzzle, you have no one to blame but yourself.
Jessica is a graduate student at UC Berkeley. The series "Science in Sacramento" was born out of her interest and involvement in both science and local politics. As an informed scientist, she feels everyone should know that graduate student loans are no longer subsidized and sometimes plants eat birds.