SPEAKER: Michael Shapiro (MSU/MSRI)

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TITLE:  Hurwitz numbers and moduli spaces. <br>


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ABSTRACT: Hurwitz number is a classical combinatorial object counting
ramified coverings over two-dimensional sphere. We describe a link
between Hurwitz numbers and modern theory of moduli spaces of holomorphic
punctured curves. The expression of Hurwitz numbers as integrals of
tautological classes over moduli spaces lead to many useful applications.
We shall also discuss some generalization for "double Hurwitz numbers".