• 제목/요약/키워드: noncrossing path

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ENUMERATION OF NSEW-PATHS IN RESTRICTED PLANES

  • Park, Seul-Hee
    • 대한수학회지
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    • 제33권2호
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    • pp.413-421
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    • 1996
  • A path g in the plane $R^2$ is the sequence of the points $(t_0, t_1, \ldots, t_n)$, with coordinates in $Z^2$. The point $t_0$ is the starting point and the point $t_n$ is the arriving point. An elementary step of g is a couple $(t_i, t_{i+1}), 0 \leq i \leq n - 1$. We denote the length of the path g by $\mid$g$\mid$ = n.

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LARGE SCHRÖDER PATHS BY TYPES AND SYMMETRIC FUNCTIONS

  • An, Su Hyung;Eu, Sen-Peng;Kim, Sangwook
    • 대한수학회보
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    • 제51권4호
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    • pp.1229-1240
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    • 2014
  • In this paper we provide three results involving large Schr$\ddot{o}$der paths. First, we enumerate the number of large Schr$\ddot{o}$der paths by type. Second, we prove that these numbers are the coefficients of a certain symmetric function defined on the staircase skew shape when expanded in elementary symmetric functions. Finally we define a symmetric function on a Fuss path associated with its low valleys and prove that when expanded in elementary symmetric functions the indices are running over the types of all Schr$\ddot{o}$der paths. These results extend their counterparts of Kreweras and Armstrong-Eu on Dyck paths respectively.