A vanishing theorem for characteristic classes of odd-dimensional manifold bundles

By Johannes Ebert. 2009

55 citations recorded by the source corpus.

We show how the Atiyah-Singer family index theorem for both, usual and self-adjoint elliptic operators fits naturally into the framework of the Madsen-Tillmann-Weiss spectra. Our main theorem concerns bundles of odd-dimensional manifolds. Using completely functional-analytic methods, we show that for any smooth proper oriented fibre bundle $E \to X$ with odd-dimensional fibres, the family index $\ind (B) \in K^1 (X)$ of the odd signature operator is trivial. The Atiyah-Singer theorem allows us to draw a topological conclusion: the generalized Madsen-Tillmann-Weiss map $\alpha: B \Diff^+ (M^{2m-1}) \to \loopinf \MTSO(2m-1)$ kills the Hirzebruch $\cL$-class in rational cohomology. If $m=2$, this means that $\alpha$ induces the zero map in rational cohomology. In particular, the three-dimensional analogue of the Madsen-Weiss theorem is wrong. For 3-manifolds $M$, we also prove the triviality of $\alpha: B \Diff^+ (M) \to \MTSO (3)$ in mod $p$ cohomology in many cases. We show an appropriate version of these results for manifold bundles with boundary.

Subfields: Algebra and Number Theory, Mathematical Physics

View Paper: https://www.semanticscholar.org/paper/057c16f8ea6d5115e8a751b64fa3193bb2948a33

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In Algebra and Number Theory

  1. O. Randal-Williams
  2. B. Botvinnik
  3. Søren Galatius
  4. Johannes Ebert

In Mathematical Physics

  1. O. Randal-Williams
  2. Johannes Ebert
  3. B. Botvinnik
  4. Søren Galatius
  5. Nathalie Wahl
  6. Andrew Putman
  7. Steven V. Sam
  8. Benson Farb

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