摘要：The permanence of a single-species population discrete model with feedback control is considered.
We found that if we use the method of comparison theorem, then the additional condition, to some
extent, is necessary. But for the system itself, this condition may not be necessary. Here, we use new
methods instead of the comparison theorem to get the permanence of the system in consideration;
the additional condition in Chen's paper (2007) is deleted.
