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Propagators associated with Morse functions. A formula for the Theta-invariant of framed 3-manifolds from Heegaard diagrams.

Friday, 16 September, 2011 - 12:30
Prénom de l'orateur : 
Christine
Nom de l'orateur : 
Lescop
Résumé : 

The Theta-invariant of a framed rational homology 3-sphere is the sum of the Casson-Walker invariant and a Pontrjagin number associated with the framing. It can be defined as the algebraic intersection of three $4$-dimensional chains, called propagators, in a configuration space. I shall describe explicit propagators associated with Morse functions coming from Heegaard diagrams (constructed with G. Kuperberg),
and present a combinatorial formula for the Theta-invariant from Heegaard diagrams.

Institution de l'orateur : 
Institut Fourier
Thème de recherche : 
Topologie
Salle : 
04
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