1. A method to propagate relations between a first rule set and a second rule set where the first and second rule sets are invoked by a common workflow model, the method comprising: tracing paths forward through the workflow model from the first rule set to the second rule set, enumerating relations that extend forward from the first rule set to the second rule set, and using multi-valued logic, calculating the effects on the relations of control flow through the workflow model from the first rule set to the second rule set.