theorem
  ((- lambda) * A) `1 = - lambda * A `1 &
  ((- lambda) * A) `2 = - lambda * A `2
proof
  ((- lambda) * A) `1 = (- (lambda * A)) `1 by RLVECT_1:79
  .= - (lambda * A) `1 by Th3;
  hence ((- lambda) * A) `1 = - lambda * A `1 by Th2;
  ((- lambda) * A) `2 = (- (lambda * A)) `2 by RLVECT_1:79
  .= - (lambda * A) `2 by Th3;
  hence thesis by Th2;
end;
