static Set<S> ai_factsFromNewFacts(LS newFacts) {
  Pair<L<IfThen>, LS> p = ai_rulesAndFacts();
  ret ai_deriveFacts(p.a, concatLists(newFacts, p.b));
}

static Set<S> ai_factsFromNewFacts(S... newFacts) {
  ret ai_factsFromNewFacts(asList(newFacts));
}