reserve A,B,C for Ordinal;
reserve a,b,c,d for natural Ordinal;
reserve l,m,n for natural Ordinal;
reserve i,j,k for Element of omega;
reserve x,y,z for Element of RAT+;
reserve i,j,k for natural Ordinal;

theorem Th48:
  x*'{} = {}
proof
  numerator {} = {} & (numerator x)*^{} = {} by Def8,Lm1,ORDINAL2:35;
  hence thesis by Th40;
end;
