Abstract by
Professor Seppo Rickman

University of Helsinki, Finland

Quasiregularly elliptic manifolds

A basic question in the theory of quasiregular maps has been the following existence problem: Given two oriented and connected Riemannian n-manifolds M and N, does there exist a nonconstant quasiregular map of M into N? The interesting case is when M is noncompact. In particular, if M=R^n and such a map exists, Gromov calls N quasiregularly elliptic. We will consider the quasiregular ellipticity problem for N closed. The case n=2 is classical and the case n=3 is pretty well understood in terms of the fundamental group. Apart from some special examples not much was known until recently for n>3. A break-through result was obtained by M. Bonk and J. Heinonen in 2001 when they proved that the dimension of the de Rham cohomology ring of N has an upper bound depending only on n and K for a K-quasiregular map of R^n into N. In the talk various questions related to the quasiregular ellipticity problem are discussed including the ideas in the proof of the theorem of Bonk and Heinonen.

Thursday, April 3, 2003, 4:00 p.m.  - 245 Altgeld Hall
MATHEMATICS COLLOQUIUM

Mathematics Colloquia homepage