A CSP is a tuple (Z, D, C), where Z is a finite set of variables, D defines a finite set Dx, called the domain of x, for each x 2 Z, and C is a finite set of constraints restricting the combination of values that the variables can take。
可以理解为
z = {x1 , x2 , x3 ... xn}
D = {D1 , D2 , D3 , ... ,Dn} 其中Di = ai,bi为xi的范围
C = {C1 , C2,...,Cm} 其中Cj = 一个限制条件，例如 x1 + x2 > 10
CSP 可以简单理解为一个多元方程寻求最优解，实际举例有n皇后问题，有点像多模态。
用LS来解决有很大好处：\[\]
(1) they use very little memory---usually a constant amount; and (2) they can often find reasonable solutions in large or infinite (continuous) state spaces for which systematic algorithms are unsuitable.