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  <body> <b><span style="text-decoration: underline;">Orateur:</span> Christine
      Lescop (Grenoble)<br>
      <span style="text-decoration: underline;">Titre:</span> Counting graph configurations in 3-manifolds. </b><br>
    <span style="font-weight: bold;"><span style="text-decoration: underline;">Résumé:</span>
    </span>We will present ways of counting configurations of uni-trivalent
    Feynman graphs in 3-manifolds in order to produce invariants of these
    3-manifolds and of their links, following Gauss, Witten, Bar-Natan,
    Kontsevich and others.
    We will first review the construction of the simplest invariants that can be
    obtained in our setting. These invariants are the linking number and the
    Casson invariant of integer homology 3-spheres.
    Next we will see how the involved ingredients allow us to define a functor
    on the category of framed tangles in rational homology cylinders, and we
    will show the properties of our functor, which generalizes both a universal
    Vassiliev invariant for links in the ambient space and a universal finite
    type invariant of rational homology 3-spheres.
    Finally, we will show how these constructions work in an equivariant setting
    in order to produce a far more structured invariant, which conjecturally
    lifts the previous one for null-homologous knots.<br>
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