test rulebase (implication) rule label friend tb x y Steph buy person merchant object keep person object own person object friend Jane constant b test 12 tomorrow 2002-10-10T17:00:00Z test12 Jack y Frank some relation role_name1role 1 constant a constant b constant b role_name2role 2 another relation constant c constant d role_name3role 3 yet another relation constant b constant e constant b role_name3role 3