---
date: 2022-04-05 23:42
modification date: Sunday 24th April 2022 14:03:27
title: "purity theorem"
aliases: [purity theorem, purity]
---

Last modified date: <%+ tp.file.last_modified_date() %>

---
- Tags: 
	- #todo/untagged
- Refs:
	- #todo/add-references
- Links:
	- #todo/create-links 

---

# purity theorem

- Gives rise to Gysin sequences?
  
![](attachments/Pasted%20image%2020220424141938.png)

![](attachments/2023-01-11-2.png)
![](attachments/2023-01-11-4.png)

# Applications

![](attachments/Pasted%20image%2020220424140339.png)