Categoria:
Seminari di Algebra e Geometria
Data e ora inizio evento:
Data e ora fine evento:
Aula:
Sala di Consiglio
Sede:
Dipartimento di Matematica, Sapienza Università di Roma
Speaker:
Vito Felice Zenobi (Sapienza Università di Roma)
The analytic surgery sequence is a long exact sequence of K-theory groups which combines
topological information (the K-homology of manifolds), index theoretic information (the
K-theory of group C*-algebras), and secondary index information (the analytic structure
group of Higson-Roe). We will see how to give a definition of terms based entirely on
algebras of pseudodifferential operators and their K-theory. We use this to systematically
develop maps to an exact sequence of non-commutative de Rham homology/cyclic
homology. Via pairings with cyclic cohomology classes, this gives rise to new numeric
secondary index invariants (higher rho numbers) with explicit formulas and calculation tools
due to the compatibility in the whole sequence. We use this for geometric applications. In
particular, we derive new information about the moduli space of Riemannian metrics of
positive scalar curvature, where we give new lower bounds on the number of its
components.