---
date: 2021-11-04 01:20
modification date: Thursday 4th November 2021 01:20:35
title: Rohklin's theorem
aliases: [Rohklin's theorem]

---

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

---

- Tags: 
	- #geomtop/4-manifolds 
- Refs:
	- #todo/add-references
- Links:
	- #todo/create-links 

---


# Rohklin's theorem

If $X^4$ is a smooth closed [spin manifold](Unsorted/spin.md) (so $w_2(X) = 0$), then the [signature](Unsorted/signature.md) of the intersection form is divisible by 16.

![Pasted image 20211104012039.png](Pasted%20image%2020211104012039.png)