Hi, I'm having difficulty understanding this definition.
http://upload.wikimedia.org/math/8/f...d7e81e87d7.png of real numbers is called Cauchy, if for every positive real number ε, there is a positive integer N such that for all natural numbers m, n > N
It seems simple, but the point I don't understand is N. What is it? What is the function of it?
I'll be grateful if you could explain this to me. Thanks in advance!