May 14, 2000
Joachim Rosenthal
Title: Pole placement problems, inverse eigenvalue problems and quantum Schubert calculus
Several prominent problems originating in linear algebra and in control theory are through their nature actually problems in algebraic geometry. Examples include a large class of so called matrix extension problems, studied in the linear algebra literature as well as most pole placement problems studied in the linear systems theory literature. In this talk we will explain those different links and we will report on several recent results obtained by geometric techniques. We will show how many of those problems have an interpretation in terms of Schubert calculus and that some of the more prominent problems require computations in the quantum ring of the Grassmannian. The presented results represent joint work with Bill Helton, Meeyoung Kim, M.S. Ravi, Frank Sottile and Alex Wang.