Herbert Grötzsch

Camillo Herbert Grötzsch was a German mathematician who lived from 1902 to 1993 and is known primarily for his work on complex analysis, specifically univalent functions and conformal mappings, and on graph theory. He was the first to introduce the concept of a quasiconformal mapping. He is also the discoverer and eponym of the Grötzsch graph, a triangle-free graph that needs four colors in any graph coloring, and of Grötzsch's theorem, the result that every triangle-free planar graph requires at most three colors. The entry is written from the lead of his English Wikipedia article.