reserve I, G, H for set, i, x for object,
  A, B, M for ManySortedSet of I,
  sf, sg, sh for Subset-Family of I,
  v, w for Subset of I,
  F for ManySortedFunction of I;
reserve X, Y, Z for ManySortedSet of I;

theorem
  EmptyMS I is empty-yielding finite-yielding MSSubsetFamily of M
by PBOOLE:43,PBOOLE:def 18;
