5 CONSTRAINT SATISFACTION PROBLEMS

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5CONSTRAINTSATISFACTIONPROBLEMSInwhich weseehowtreatingstatesasmore thanjustlittleblack boxesleadsto theinventionofa range ofpowerfulnew search methodsanda deeperunderstandingofproblemstructure and4 exploredtheideathatproblemscanbesolvedby searchinginaspaceofstates. Thesestatescanbeevaluatedbydomain-specif icheuristicsandtestedtoseewhetherthey ,however,eachstateis is representedbyanarbi-BLACKBOXtrarydatastr ucturethatcanbeaccessedonlybytheproblem- specificroutines thesuccessorfunction,heuristicfunction, , whosestatesandgoaltestconformtoa standard,structured,andverysimplereprese ntation( ).Searchal-REPRESENTATIONgorithmscanbede finedthattake advantageofthestructureofstatesandusegen eral-purposeratherthanproblem-specifiche uristicsto enablethesolutionoflargeproblems( ).

search problem as follows:}Initial state: the empty assignment fg, in which all variables are unassigned.}Successor function: a value can be assigned to any unassigned variable, provided that it does not conflict with previously assigned variables.}Goal test: the current assignment is complete.}Path cost: a constant cost (e.g., 1) for every step.

  Satisfaction, Problem, Assignment, Constraints, Constraint satisfaction