Prof. Heinz-Otto Kreiss

The existence of computers has made it possible to solve linear and nonlinear partial differential equations (PDEs) numerically. This possibility has lead to an enormous activity to develop numerical techniques and to understand their behavior theoretically. It also stimulated the development of a general theory of partial differential equations. Using time dependent problems as an example we will discuss the concepts and results of this development and show that we have a rather good understanding of the basic theory. Of course, there are lots of open problems and we will discuss some of them.