This page gathers information on constraints in a popular form of questions and answers. I expect it to evolve into reach and useful part of the site. If you have any comments or corrections to answers presented in this page, don't hesitate to contact me .
Constraint programming is the study of computational systems based on constraints.
The optimisation aspect is emphasised in CP trough the use of a special additional constraint that is tighted when a solution is find. These algorithms are easier to understood but their ideas can be converted to n-ary constraints. Most practical applications work with n-ary constraints directly. In fact, binarization with original variables is included implicitely in such algorithms. There are also some workshops on practical applications organized within other conferences.