Abstract: Euler characteristic is one of the most basic invariants of topological spaces. It is relatively easy to compute, but carries substantial information about the homotopy type of a space. The talk will show how these properties of Euler characteristic has led to its various generalizations: in the algebraic K-theory, Waldhausen's A-theory and, most recently, in the work of Dwyer, Weiss and Williams on homotopy types of fibrations.

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If you are interested in giving a talk, please contact Dr. Juan Gil, the Colloquium Coordinator for the Fall 2005 semester.