German-American mathematician
Heinz Otto Cordes (March 18, 1925 – October 30, 2018) was a German-American mathematician, specializing in partial differential equations (PDEs). He is known for the Aronszajn–Cordes uniqueness theorem for solutions of elliptic PDEs (due independently to Nachman Aronszajn).
Biography.
At the University of Göttingen, Cordes received in 1952 his doctorate. His doctoral dissertation, supervised by Franz Rellich, is entitled "Separation von Variablen in Hilbertschen Raumen" (Separation of variables in Hilbert spaces). Cordes held a junior academic appointment at Göttingen from 1952 to 1956, when he was appointed to an assistant professorship at the University of Southern California. At the University of California, Berkeley (UC Berkeley), he was an assistant professor to 1958 to 1959, an associate professor from 1959 to 1963, and a full professor from 1963 to 1991, when he retired as professor emeritus. In retirement he remained active in research.
Cordes made a number of significant contributions to the theory of PDEs. He also introduced C*-algebra techniques to define the symbol of elements of algebras of singular integral operators (as well as algebras of pseudodifferential operators). Thereby he extended the operator symbol calculus from compact manifolds to various classes of non-compact manifolds. This research led him to study Dirac operators with their connections with relativistic quantum mechanics. He was the author of 4 books and the author or co-author of more than 60 articles. From 1963 to 1999, he sometimes collaborated with Tosio Kato.
Cordes received an Alfred P. Sloan fellowship in 1959. He declined an invitation to address the International Congress of Mathematicians held in Moscow in 1966. For the academic year 1971–1972, Cordes was a visiting professor at Lund University, where he gave a course on pseudodifferential operators via a C*-algebra approach. His 19 doctoral students at UC Berkeley include Michael G. Crandall and Michael E. Taylor.
Upon his death in 2018, Heinz Cordes had been married to his wife Hillgia for 63 years. They were the parents of a son and two daughters.