theorem Th11:
  ex T being DivSequence of A st delta(T) is convergent & lim
  delta(T)=0
proof
  now
    per cases;
    suppose
A1:   vol(A)<>0;
      vol(A) >= 0 by INTEGRA1:9;
      hence thesis by A1,Lm5;
    end;
    suppose
      vol(A)=0;
      hence thesis by Lm6;
    end;
  end;
  hence thesis;
end;
