What is the math behind sudoku?

Related questions

1. What is the hardest sudoku puzzle ever?
2. Can a sudoku puzzle be unsolvable?
3. Is there any formula for Sudoku?
4. What are good sudoku times?
5. Do Sudoku make you smarter?
6. What is a pointing pair in Sudoku?
7. Do diagonals count in Sudoku?
8. Is sudoku good for your brain?
9. How long should it take to solve a hard Sudoku?
10. Does Sudoku make you better at math?

Tags

1. #mathematical
2. #logical
3. #cells
4. #deduction
5. #contradict
6. #solve
7. #sudoku
8. #thinking
9. #basic
10. #strategy
11. #write
12. #respect
13. #given
14. #sudokus
15. #possible
16. #entries
17. #first
18. #empty
19. #useful
20. #puzzle
21. #solving