static <A extends Concept> ConceptFieldIndexCI<A> indexConceptFieldCI(Class<A> c, S field) {
  ret indexConceptFieldCI(db_mainConcepts(), c, field);
}

static <A extends Concept> ConceptFieldIndexCI<A> indexConceptFieldCI(Concepts concepts, Class<A> c, S field) {
  ConceptFieldIndexCI<A> idx = getConceptFieldCIIndex(concepts, c, field);
  ret idx != null ? idx : new ConceptFieldIndexCI(concepts, c, field);
}