.predicate(Playground.AGE, "?person", "?age").predicate(new LT(), "?age", 30));
}
public static void doubleAges() {
Api.execute(new StdoutTap(), new Subquery("?person", "?double-age")
.predicate(Playground.AGE, "?person", "?age").predicate(new Multiply(), "?age", 2)
.out("?double-age"));
}