Per Enflo | |
|---|---|
.jpg) Enflo in 1972 | |
| Born | 20 May 1944 |
| Alma mater | Stockholm University |
| Known for | Approximation problem Schauder basis Hilbert's fifth problem (infinite-dimensional) uniformly convex renorms of super-reflexive Banach spaces embedding metric spaces (unbounded distortion of cube) "Concentration" of polynomials at low degree Invariant subspace problem |
| Awards | Mazur's "live goose" for solving "Scottish Book" Problem 153 |
| Scientific career | |
| Fields | Functional analysis Operator theory Analytic number theory |
| Institutions | University of California, Berkeley Stanford University École Polytechnique, Paris The Royal Institute of Technology, Stockholm Kent State University |
| Doctoral advisor | Hans Rådström |
| Doctoral students | Angela Spalsbury Bruce Reznick |
Per H. Enflo (Swedish: [ˈpæːr ˈěːnfluː]; born 20 May 1944) is a Swedish mathematician working primarily in functional analysis, a field in which he solved problems that had been considered fundamental. Three of these problems had been open for more than forty years:[1]
- The basis problem and the approximation problem[2] and later
- the invariant subspace problem for Banach spaces.[3]
In solving these problems, Enflo developed new techniques which were then used by other researchers in functional analysis and operator theory for years. Some of Enflo's research has been important also in other mathematical fields, such as number theory, and in computer science, especially computer algebra and approximation algorithms.
Enflo works at Kent State University, where he holds the title of University Professor. Enflo has earlier held positions at the Miller Institute for Basic Research in Science at the University of California, Berkeley, Stanford University, École Polytechnique, (Paris) and The Royal Institute of Technology, Stockholm.
Enflo is also a concert pianist.
- ^ Page 586 in Halmos 1990.
- ^ Per Enflo: A counterexample to the approximation problem in Banach spaces. Acta Mathematica vol. 130, no. 1, Juli 1973
- ^ *Enflo, Per (1976). "On the invariant subspace problem in Banach spaces". Séminaire Maurey--Schwartz (1975--1976) Espaces Lp, applications radonifiantes et géométrie des espaces de Banach, Exp. Nos. 14-15. Centre Math., École Polytech., Palaiseau. p. 7. MR 0473871.
- Enflo, Per (1987). "On the invariant subspace problem for Banach spaces". Acta Mathematica. 158 (3): 213–313. doi:10.1007/BF02392260. ISSN 0001-5962. MR 0892591.