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;

theorem :: SETFAM_1:4
  G in sf implies Intersect sf c= G
proof
  assume
A1: G in sf;
  then meet sf = Intersect sf by SETFAM_1:def 9;
  hence thesis by A1,SETFAM_1:3;
end;
