COREFERENCING RULE SET FOR THIS INPUT:

At this point, the tree structure in Figure 1 is analyzed with respect to the dependencies present among each rule. A constraint propagation function is used which currently can utilize the following propagation types:

• desc - all descendants
• children - children only, not their descendants
• parent - parent only
• parent-desc - parents and all their descendants
• grandparent - grandparent only
• grandparent-desc - grandparent and descendants
• sisters - sisters
• sisters-desc - sisters and their descendants
• (node node) - a particular node
• (node-desc node) - a particular node and its descendants

For each constraint, it is determined which nodes it can affect by using the propagation function. After recording the constraint information, the following indices are set up:

• *effects* for each rule, records list of constraints that will be imposed if rule is applied.
• *eff-deps* for each constraint, records list of rules that would, if instantiated, cause effects that would conflict with the constraint.
• *con* for each constraint records a list of rules that can originate it.
• *dependencies* for each rule records a list of constraints which, if applied, would conflict with this test's dep rules.
• *dep-deps* for each constraint, records a list of rules which would be prevented by applying the constraint. For example, if a certain constraint would invalidate any rule's precondition, the effected rule would be included.
• *needed* for each rule, returns a list of rules that could satisfy needed constraints.

These indices contain all the information needed about the inter-dependencies that exist in the current set of active rules. For RELATION-20 in this example, the following information would be recorded.

• *NEEDED*
• *EFFECTS*
• *EFF-DEPS*
• *CON*
• *DEPENDENCIES*
• *DEP-DEPS*