# Monday, June 28


![](figures/2021-06-28_22-21-50.png)


![](figures/2021-06-28_22-22-27.png)


![](figures/2021-06-28_22-22-56.png)


![](figures/2021-06-28_22-23-40.png)


![](figures/2021-06-28_22-24-27.png)

Why cobordism matters here:

![](figures/2021-06-28_22-26-20.png)