Erik Christensen retires after 50 years with mathematics
From 1 May 2015 Erik Christensen will be emeritus at the Department of Mathematical Sciences. It will be marked by a week-long conference, and by Eric's own retirement lecture on Thursday 7 May.
Erik Christensen's person and his work is celebrated by a conference featuring most of Erik's collaborators as speakers - emphasizing the many areas of operator algebras that Erik has influenced. The conference Operator Algebras and Applications is held 4-8 May 2015 at the Department of Mathematical Sciences. The conference is organized by the Centre for Symmetry and Deformation.
On 7 May at 14:15 Erik will give his retirement lecture, "Fifty years with mathematics" in auditorium 3. This is his abstract:
"I met Euclidian geometry in the plane when I was 12, and I was happy to learn to make small sketches which described facts about geometrical figures and then give exact proofs based on such drawings. Since then concrete mathematical problems and abstract mathematical ideas has taken up a good part of my time, but I have been distracted by love, wife, children, housekeeping, teaching, administration and so on. I will tell a little about some of the experiences I have had. "
After the lecture the MATH Department host a reception at 15:00 in the lunch room on the 4th floor (04.4.19).
From the conference "Operator Algebras and Applications”, 5 May 2015.
EC was born April 5, 1945, in Dandung China. While not born, Erik is certainly bred in Copenhagen. He obtained his A-levels from Christianshavns Gymnasium i 1964 and served his military duty in the years 1964-65. He got his master degree in mathematics from the University of Copenhagen in 1970 with Esben Kehlet as his supervisor.
From 1970 until 1975 he visited various universities; in particular he spent the academic year 1973/74 in Oslo. Since that time he has very good relations with the Norwegian group of operator algebraists in Oslo and Trondhjem, as well as with Richard Kadison, one of the founding fathers of the subject.
Since 1975 Erik was employed by the University of Copenhagen, first as lector and since 1989 as docent. In 1984 Erik defended his thesis for the doctor of science degree.
Alone, or in collaboration with others, Erik has published 43 papers in international journals (at the moment 3 papers are accepted for publication). His work had and still has an essential influence on some of the active areas of the theory of operator algebras.
During the years the focus of Eric’s research has changed, but most of the articles fall into one of the following groups: perturbations of algebras of operators, the similarity question for C*-algebras, inclusions of finite von Neumann algebras, measures on projections, completely bounded multilinear mappings, Hochschild cohomology for operator algebras and non-commutative geometry.
The latest work of Erik has two distinct directions:
One of them, joint with various co-authors, is related to some basic questions in Non-commutative Geometry. An important example of this direction is the latest work with Cristina Ivan at the M. D. Anderson cancer center in Houston Texas, USA. Pursuing the ideas and methods of their previous joint work they study some concrete degenerations of a family of spectral triples on a C*-algebras obtained as extensions by the algebra of compact operators. In particular, several models of this type are motivated by and appear in mathematical physics.
The second project centers around an old interest of Erik, the study of perturbation of C*-algebras. This work involves collaboration with Allan M. Sinclair, Univ. of Edinburgh, Roger R. Smith, Texas A&M, Stuart White, Univ. of Glasgow and Wilhelm Winter, Univ. of Münster. One of the major results obtained to date is the proof of the surprising fact that two sufficiently close separable and nuclear C*-algebras are unitarily equivalent.
The long list of seminars and conferences that Erik participated in includes countries like Canada, China, Finland, France, Germany, Holland, Ireland, Japan, Norway, Poland, Romania, Sweden, UK and USA.
As a teacher Erik has taught many different mathematics courses on all levels - from service courses for biology or economics students to advanced graduate courses for PhD students and colleagues.
On the administrative side Erik has served on many boards and committees of the institute. He was the head of the study board from 1980 to 1982 and the chairman for the Mathematics Department from 1990 to 1992.
