---
created: 2026-04-08 10:32
course: "[[29593850 - Automationtheory]]"
topic: languages
related: "[[29593940 - Formal Languages]]"
type: lecture
status: 🔴
tags:
  - university
---
## 📌 Summary

> [!abstract]
> 

---

## 📝 Content

A language $L$ that can be described by a [[29593975 - Regular Expressions|Regular Expression]] $r$ (i. e. $L(r) = L$) is called _regular_.

> [!WARNING]
> There a several important languages that **cannot** be described by a regular expression.
> <mark style="background: #CACFD9A6;">(proof later)</mark>