On a general framework for large-scale constraint-based optimization

The explicit solution for the n–queens problem, mentioned in a letter from Bo Bernhardsson [2], is basically Pauls's solution analyzed by Ahrens (See reference [1] of our previous article in SIGART October issue 1990). The result was in public domain long before 1918 (not 1969). We also mentioned its weakness, namely: The class of solutions provided by analytical methods is very restricted, as Ahrens pointed out in [1]. They can only provide one solution for the n–queens problem and can not provide any solution (much better explicit solutions for the n–queens problem exist). This is not the case for search methods which can find, in principle, any solution. This distinction is crucial for practical applications of the n-queens problem.