This is an old revision of the document!
A sample.
I will try to summarize what I understand in my own words. It may contain errors or misundertandings of concepts, but at least that's where I am standing now, and we can improve from here.
1. What does lim sup mean? How is it different from just sup?
2. What is the difference between a set and sequence? Aren't they just a bunch of numbers?