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math104-s21:s:xingjiantao

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Xingjian Tao's Notes and Question List

Notes

I made some notes on LaTex. You can see the PDF here math104_notes.pdf. The organization of definitions and theorems is mainly based on Rudin, though supplemented by Ross. Sometimes I tried to rewrite the contents in a more symbolic way, so there maybe minor mistakes.

Question List

1. How is the definition of limit points related with the concept of limit?

Answer: An element is a limit point of $E$ iff. it is the limit of some inconstant sequence of points in $E$. Inconstant is important because the definition of limit points includes hollow neighborhoods.

2. Suppose $E$ is an infinite subset of a set $K$. Then $E$ has a limit point in $K$ iff. $K$ is compact. Prove this.

Answer: $\Longrightarrow$ can be found in 2.37 Theorem of Rudin. $\Longleftarrow$ can be found in Excercise 26 of Rudin Chapter 2.

math104-s21/s/xingjiantao.1620813405.txt.gz · Last modified: 2026/02/21 14:44 (external edit)