reserve X,Y,Z for set,
  a,b,c,d,x,y,z,u for object,
  R for Relation,
  A,B,C for Ordinal;

theorem Th2:
  for A,X st X c= A holds RelIncl X is well-ordering
proof
  let A,X;
  (RelIncl A) |_2 X is well-ordering by WELLORD1:25;
  hence thesis by Th1;
end;
