# Lüroth's theorem

> subfield of K(X) is isomorphic to K(X)

**Wikidata**: [Q3527115](https://www.wikidata.org/wiki/Q3527115)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Lüroth's_theorem)  
**Source**: https://4ort.xyz/entity/l-roth-s-theorem