theorem Th1:
  for seq be sequence of CNS holds -seq=(-1r)*seq
proof
  let seq be sequence of CNS;
  now
    let n;
    thus ((-1r)*seq).n =(-1r)*seq.n by CLVECT_1:def 14
      .=-seq.n by CLVECT_1:3
      .=(-seq).n by BHSP_1:44;
  end;
  hence thesis by FUNCT_2:63;
end;
