friend tb x y Steph (implication) rule label friend Jane Joan Jack y Frank friend tb x y Steph (implication) rule label friend Jane Joan Jack y Frank friend Jane Joan Jack y Frank some relation role_name1role 1 constant a constant b role_name2role 2 another relation constant c constant d some relation role_name1role 1 constant a constant b role_name2role 2 another relation constant c constant d rule (query) label rule (fact) label yet another relation constant e constant b role_name3role 3 test rulebase