Willi Jäger (born 15 August 1940 in Kschellowitz, Bohemia) is a German mathematician.
In 1987 Jäger was founding member of the Interdisciplinary Center for Scientific Computing in Heidelberg.
[citation needed] In addition to problems of scientific computing, including the effective use of computers for the mathematical modeling of complicated, mostly scientific problems, Jäger deals with problems of nonlinear differential equations, calculus of variations, branching processes, and the spectral theory of differential operators, mostly with a view to specific applications such as data visualization.
Thus far, he has been honoured with 2 honorary doctorates,[citation needed] several prizes and the Order of Merit of the Federal Republic of Germany.
Jäger had more than 100 PhD students, including Florin Diacu, Bernold Fiedler, Stephan Luckhaus, Hubert Mara and Martin Vingron.