# A briefing of Topology's most important definitions and results?

## Main Question or Discussion Point

I just need to know the basic ideas of topology, and the most important results, because I'll have differential geometry the next semester. Does anyone have a good material for this? Or you can just say what to search for and I'll search it. Thank you :)

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I just need to know the basic ideas of topology, and the most important results, because I'll have differential geometry the next semester. Does anyone have a good material for this? Or you can just say what to search for and I'll search it. Thank you :)
You really should understand topology pretty well before you do differential geometry. I found Munkres to be a good start, if you want to look for it. I happen to know that there are a couple copies wandering the internet.

The basics:

A topology, which I shall call ##\mathscr{T}##, on a space ##S## is a collection of sets contained in ##S## such that the following are satisfied:

1. ##S## and ##\emptyset## are in ##\mathscr{T}##
2. The union of elements in any subcollection of ##\mathscr{T}## is in ##\mathscr{T}##
3. The intersection of elements in any finite subcollection of ##\mathscr{T}## is in ##\mathscr{T}##

Elements of the topology are called open sets. A pairing ##(S,\mathscr{T})## is called a topological space.

mathman
I disagree somewhat. My first exposure to differential geometry did not require any topology. The main prerequisites would be linear algebra and calculus.

I just need to know the basic ideas of topology, and the most important results, because I'll have differential geometry the next semester. Does anyone have a good material for this? Or you can just say what to search for and I'll search it. Thank you :)
Chapters 2-4 of Lee, Topological Manifolds might be useful.

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