Seminars in November 2010

  • Heesung Shin (신희성), On q-enumeration of permutations
    On q-enumeration of permutations
    Heesung Shin (신희성)
    Department of Mathematics, POSTECH, Pohang, Korea
    2010/11/19 Fri 4PM-5PM
    Laguerre histories are certain colored Motzkin paths with some weight for each elementary steps. In this talk, we study two famous bijections between permutations and Laguerre histories, made by Francon-Viennot and Foata-Zeilberger. This two bijections are enable us to give permutations as combinatorial interpretations of continued fractions. The former is associated in linear statistics and the latter be in cyclic statistics. Using two mappings, we are able to make various results about several statistics of permutations.
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  • Greg Markowsky, Distance-Regular Graphs and Potential Theory
    Distance-Regular Graphs and Potential Theory
    Greg Markowsky
    Pohang Mathematics Institute, POSTECH, Pohang, Korea
    2010/11/4 Thu 4PM-5PM (Room 3433)

    The study of electric potentials on graphs has a close connection with probability theory. On distance-regular graphs the theory is particularly elegant, as known results concerning such graphs allow explicit calculations to be made. In this talk, I will introduce these topics and discuss some recent results that Jacobus Koolen and I have obtained, as well as some conjectures and open problems.

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