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An Isaac Newton Institute Workshop

Noncommutative Geometry and Cyclic Cohomology

A new homology theory on rings : the stabilized Witt groups

Author: Max KAROUBI (Université Paris 7)


We define a new homology theory defined on discrete rings with involution (even when 2 is not invertible). This theory sastisfies excision, homotopy invariance, periodicity (of period 4) and other nice properties. It is closely related to Balmer's theory and to surgery groups. When A is a real or complex C*-algebra, we recover topological K-theory (up to 2-torsion).

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