Changing a rule set affects queries made after the change. Some queries may have been previously compiled and will not be changed as a result of modifying the rule set. When a rule set is changed, i.e. when rdfs_rule_set is called with the first argument set to a pre-existing rule set's name, all the graphs associated with this name are read and the relevant facts are added to a new empty rule set. Thus, if triples are deleted from or added to the graphs comprising the rule set, calling rdfs_rule_set will refresh the rule set to correspond to the state of the stored graphs.