theorem Th16:
  seq is convergent implies lim (- seq) = - (lim seq)
proof
  assume seq is convergent;
  then lim ((-1r) * seq) = (-1r) * (lim seq) by Th15;
  then lim (- seq) = (-1r) * (lim seq) by CSSPACE:70;
  hence thesis by CLVECT_1:3;
end;
