|Title: Transversality defect of two lagrangians and ternary index. Application: Formulas of (non) additivity of signatures and of linking forms|
|Speaker: Jean Barge of Ecole polytechnique|
|Contact: David Zureick-Brown, firstname.lastname@example.org|
|Date: 2014-04-29 at 4:00PM|
(This is a common work with Jean Lannes) To a pair of lagrangians in a symplectic space, we associate a symetric bilinear form well defined up to the addition of non-degenerate forms and which is itself non-degenerate if and only if the two lagrangians are transversal. To a triple of lagrangians, we associate a ternary index which is a raffinement of the Leray-Kashiwara index and which generalizes for any (commutative) ring the index defined by Wall for fields. We will explain how these two invariants can be used to compute signatures and linking forms of manifolds obtained by gluing.
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