K-Theory Day
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Mon, 10/11/2008 14:15 |
Thomas Schick (Goettingen) |
Geometry and Analysis Seminar  K-Theory Day |
L3 |
| Let M be a closed spin manifold. Gromov and Lawson have shown that the presence of certain "enlargeable" submanifolds of codimension 2 is an obstruction to the existence of a Riemannian metric with positive scalar curvature on M. In joint work with Hanke, we refine the geoemtric condition of "enlargeability": it suffices that a K-theoretic index obstruction of the submanifold doesn't vanish. A "folk conjecture" asserts that all index type obstructions to positive scalar curvature should be read off from the corresponding index for the ambient manifold M (this this is equivalent to a small part of the strong Novikov conjecture). We address this question for the obstruction above and discuss partial results. | |||
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Mon, 10/11/2008 15:45 |
Siegfried Echterhoff (Goettingen) |
K-Theory Day Topology Seminar |
L3 |
| We study non-commutative analogues of Serre-ï¬~Abrations in topology. We shall present several examples of such ï¬~Abrations and give applications for the computation of the K-theory of certain C*-algebras. (Joint work with Ryszard Nest and Herve Oyono-Oyono.) | |||
