message: Predicate fix
diff: @@ -64,7 +64,7 @@ namespace Predicates {
  export function or(...ps: Atom.Predicate[]): Atom.Predicate {
  switch (ps.length) {
  - case 0: return P.constant.true;
  + case 0: return P.constant.false;
  case 1: return ps[0];
  case 2: {
  const a = ps[0], b = ps[1];
  