Udo Pachner (1947-2002) - A 'Hidden Champion' in Mathematics

Udo Pachner proved that all simplicial manifolds which are homeomorphic can be transformed into each other by a sequence of simple transformations now commonly called "Pachner moves". For a fixed dimension there are only finitely many types of Pachner moves. This makes it possible to identify invariants by proving the invariance only for a finite number of transformations. This fact has proved useful for various applications in p.l. topology and in loop quantum gravity theory. The paper is meant to honor the importance of Pachner's results and to make them known to a wider community.