CRChristian Reiher
Hamburg, Germany · academicChristian Reiher (born 19 April 1984 in Starnberg am See, Bavaria) is a German mathematician at the University of Hamburg, working in extremal and arithmetic combinatorics and structural Ramsey theory. The eldest child of Gymnasiallehrer Werner Reiher and Sigrid Reiher (nee Hermann), he grew up in Pfaffenhofen an der Ilm, attended the Schyrengymnasium there and passed the Abitur in June 2003. A six-time national winner of the Bundeswettbewerb Mathematik, he represented Germany at the International Mathematical Olympiad from 1999 to 2003, winning a bronze medal and four golds. He studied mathematics with a minor in theoretical physics at LMU Munich from 2003, spent 2006/07 as a guest student in Oxford's logic and model theory group, and graduated as a Diplom-Mathematiker in 2008 with a thesis on inaccessible Jonsson cardinals. He earned his doctorate at the University of Rostock in 2010 under Hans-Dietrich Gronau, proved Kemnitz's conjecture, co-authored the clique density theorem (Annals of Mathematics, 2016), and received the European Prize in Combinatorics in 2017.
- European Prize in Combinatorics 2017 was awarded jointly with Maryna Viazovska at Eurocomb 2017 (TU Wien) for his solution of the Kemnitz conjecture and the Lovasz-Simonovits clique density problem.Aug 28, 2017
- Received the European Prize in Combinatorics in 2017, a recognition of major early-career contributions.2017
- Co-proved the clique density theorem (Annals of Mathematics 184(3), 2016), one of the most cited results in extremal graph theory.2016
- Proved Kemnitz's conjecture on lattice points in the plane shortly after finishing his Abitur; published in The Ramanujan Journal (2007).2007
- Represented Germany at the IMO every year 1999-2003: bronze in 1999 and gold medals in 2000, 2001, 2002 and 2003; ranked 4th in 2002 (99.4%) and 12th in 2003 (97.6%).2003
- Earned Dr. rer. nat. at University of Rostock in Feb 2010 under Hans-Dietrich Gronau; thesis 'A proof of the theorem according to which every prime number possesses property B' (combinatorics, MSC 05).2010
- Fifth most successful participant in IMO history by medal count (four golds plus a bronze).
- Diplomarbeit (2008) was on the combinatorics of the infinite, specifically inaccessible Jonsson cardinals, before pivoting to finite combinatorics for his doctorate in Rostock.Sep 2008
- Spent academic year 2006/07 as a guest student at the University of Oxford, oriented toward the logic and model theory group, before returning to Munich for his Diplom.2006
- Was a six-time national winner (Bundessieger) of the Bundeswettbewerb Mathematik during his school years, the pipeline that fed his IMO career.
- Supervised at least one doctoral student, Bjarne Schulke (Universitat Hamburg, 2021), indicating he leads his own research students.2021
- Publicly lists research interests as arithmetic combinatorics, extremal combinatorics and structural Ramsey theory.
Competition record
Germany · IMO