For papers, please refer to Topology Paper Alert

# Category Archives: Topology

# Topology Resources (books, lectures, videos)

## Books

- 「位相への３０講」：集合の各要素に対し「近さ」(距離) の概念を導入すれば，位相空間になる。何かの集合や空間を定量的に扱うには，位相の考え方が必要になる。

# Handbook of Discrete and Computational Geometry (3rd Edition, 2016)

http://www.csun.edu/~ctoth/Handbook/HDCG3.html

**Previous editions:**

*Handbook of Discrete and Computational Geometry*, First Edition

J.E. Goodman and J. O’Rourke, editors,

CRC Press LLC, Boca Raton, FL, 1997.

ISBN 978-0849385247 (52 chapters, xiv + 991 pages).*Handbook of Discrete and Computational Geometry, Second Edition*

J.E. Goodman and J. O’Rourke, editors,

CRC Press LLC, Boca Raton, FL, 2004.

ISBN 978-1584883012 (65 chapters, xvii + 1539 pages).

# Notes on the Nash embedding theorem

Terence Tao notes on embedding theorem.

Throughout this post we shall always work in the smooth category, thus all manifolds, maps, coordinate charts, and functions are assumed to be smooth unless explicitly stated otherwise.

A (real) manifold $latex {M}&fg=000000$ can be defined in at least two ways. On one hand, one can define the manifold *extrinsically*, as a subset of some standard space such as a Euclidean space $latex {{bf R}^d}&fg=000000$. On the other hand, one can define the manifold *intrinsically*, as a topological space equipped with an atlas of coordinate charts. The fundamental *embedding theorems* show that, under reasonable assumptions, the intrinsic and extrinsic approaches give the same classes of manifolds (up to isomorphism in various categories). For instance, we have the following (special case of) the Whitney embedding theorem:

Theorem 1 (Whitney embedding theorem)Let $latex {M}&fg=000000$ be a compact manifold. Then there exists an embedding $latex {u: M rightarrow {bf…

View original post 4,211 more words

# Homomorphism vs Homeomorphism

Did you get the joke in the picture to the left? If not, you will do so in a few minutes. I was recently reading an article and I came across the terms mentioned in the title. From the looks of it, they are very close to each other, right? In many fields within mathematics, we talk about objects and the maps between them. Now you may ask why we would want to do that? Well, transformation is one of the most fundamental things in any field. For example, how do we transform a line into a circle, or fuel into mechanical energy, or words into numbers? There are infinitely many types of transformations that can exist. Obviously, we cannot account for every single type of transformation that can possibly exist. So we limit ourselves to only the interesting ones. So what exactly is it all about? How does it even relate to the title of…

View original post 998 more words