Constraints and Crosswords

One of the most commonly shown and studied example of Constraint Satisfaction Problem is a A crossword puzzle. For this discussion board assignment:

1. Explain a crossword puzzle problem.
2. Describe what are the variables in a crossword puzzle problem
3. Explain, what are the constraints in the crossword puzzle problem
4. Discuss a possible algorithms, that could resolve crossword puzzle problem
   Resources:
   https://cis.temple.edu/~giorgio/cis587/readings/constraints.html#2
   W7: Constraint Satisfaction Problems
   Resources to consult:
   https://cis.temple.edu/~giorgio/cis587/readings/constraints.html#2
   http://artint.info/html/ArtInt_78.html