Gerhard Hessenberg

Who was Gerhard Hessenberg?

Gerhard Hessenberg was a German mathematician. He received his Ph.D from the University of Berlin in 1899 under the guidance of Hermann Schwarz and Lazarus Fuchs. His name is usually associated with projective geometry, where he is known for proving that Desargues' theorem is a consequence of Pascal's theorem, and set theory where he is known for introducing the concept of a connection. The Hessenberg sum and product of ordinals are named for him. However, Hessenberg matrices are named for Karl Hessenberg, a near relative.