theorem Th60:
  LattStr (# Subspaces(M), SubJoin(M), SubMeet(M) #) is 01_Lattice
proof
  LattStr (# Subspaces(M), SubJoin(M), SubMeet(M) #) is lower-bounded
  upper-bounded Lattice by Th58,Th59;
  hence thesis;
end;
