A Cauchy sequence is an infinite sequence of points that get progressively closer together, eventually. No matter how small a radius you pick, there'll be a point in the sequence beyond which all points remain within that radius of each other.


  • M. F. Barnsley.  Fractals Everywhere, New Edition, Dover Publications, Inc., Mineola, New York, USA, 2012.
  • https://en.wikipedia.org/wiki/Cauchy_sequence