Joachim A. Nitsche (September 2, 1926, Nossen – January 12, 1996) was a German mathematician and professor of mathematics in Freiburg, known for his important contributions to the mathematical and numerical analysis of partial differential equations.
The duality argument for estimating the error of the finite element method and a scheme for the weak enforcement of Dirichlet boundary conditions for Poisson's equation bear his name.
Starting in summer 1947, he studied mathematics the University of Göttingen, where he received his Diplom (under supervision of Franz Rellich) after only six semesters.
He became professor at the Albert Ludwigs University of Freiburg in 1958 and received the chair for applied mathematics there in 1962.
Praktische Mathematik, BI Hochschulskripten 812*, Bibliographisches Institut, Mannheim, Zurich, 1968.