reserve a,b,c,d,x,y,z for object, X,Y,Z for set;
reserve R,S,T for Relation;
reserve F,G for Function;

theorem Th32:
  R is well-ordering implies field(R |_2 R-Seg(a)) = R-Seg(a)
proof
  R-Seg(a) c= field R by Th9;
  hence thesis by Th31;
end;
