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9 votes
3 answers
403 views

Are there invariants of cell complexes similar to the Euler characteristic?

The Euler characteristic is an invariant (under homeomorphism) of manifolds that can be computed from a cellulation by (weighted) counting of different kinds of objects, namely \begin{equation} \chi=\...
Andi Bauer's user avatar
  • 3,001
5 votes
2 answers
222 views

$\mathbb{CP}(2)$ from gluing boundary of 4-ball

Many manifolds can be obtained from gluing the boundary of a ball. For example, $\mathbb{RP}(2)$ is obtained from gluing the two edges of a bi-gon (2-ball). Or, lens spaces are obtained from a 3-cell ...
Andi Bauer's user avatar
  • 3,001
3 votes
1 answer
255 views

Handle attachment information from Morse function and triangulation

First, allow me to setup the relevant information. It is well known that a Morse function $f:M\to\mathbb{R}$ induces a handle decomposition of $M$. For simplicity, let's restrict for now to the ...
rab's user avatar
  • 159