3040	 Synthesizing Constraint Expressions	 A constraint network representation is presented for a combinatorial search problem finding values for a set of variables subject to a set of constraints. A theory of consistency levels in such networks is formulated which is related to problems of backtrack tree search efficiency. An algorithm is developed that can achieve any level of consistency desired in order to preprocess the problem for subsequent backtrack search or to function as an alternative to backtrack search by explicitly determining all solutions. Backtrack combinatorial algorithms constraint networks constraint satisfaction graph coloring network consistency relaxation scene labeling search
