# Ringel–Youngs theorem

> theorem on the number of colors needed for graphs embedded on higher genus surfaces

**Wikidata**: [Q2799491](https://www.wikidata.org/wiki/Q2799491)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Heawood_conjecture)  
**Source**: https://4ort.xyz/entity/ringel-youngs-theorem