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Show 34 3.3 Implied Restrictions on Constraint Kernel Graph . What, if any, restrictions must be placed on the dependencies and constraints in the Constraint Kernels so that the constraint kernels are a viable satisfadion strategy? Any restric· tions on the Constraint Kernels would be manifested as restrictions on the dependency graph and/or the constraint networks. By definition, a dependency graph is a directed, acyclic graph, and a constraint network is an undirected graph, with no restriction on cycles. The Constraint Kernels do not restrict In any way the definition of either a dependency graph or constraint networks. However, the interface between the dependency graph and a constraint network does require a restriction, described in section 3.1, to ensure that a one pass ordering is possible. That restriction is that cycles in the Constraint Kernels graph may not contain any objects derived by dependencies. Cycles must be contained completely within the constraint networks. |
