arXiv subjects

Sangwook Kim

Publications and source records attributed to Sangwook Kim.

21 records · Page 2Linked to original sources

arXiv2017

Enumeration of Fuss-Schröder paths

In this paper we enumerate the number of $(k, r)$-Fuss-Schröder paths of type $λ$. Y. Park and S. Kim studied small Schröder paths with type $λ$. Generalizing the results to small $(k, r)$-Fuss-Schröder paths with type $λ$, we give a combinatorial interpretation for the number of small $(k, r)$-Fuss-Schröder paths of type $λ$ by using Chung-Feller style. We also give two sets of sparse noncrossing partitions of $[2(k + 1)n + 1]$ and $[2(k + 1)n + 2]$ which are in bijection with the set of all small and large, respectively, $(k, r)$-Fuss-Schröder paths of type $λ$.

math.CO↗

arXiv2009

Flag enumerations of matroid base polytopes

In this paper, we study flag structures of matroid base polytopes. We describe faces of matroid base polytopes in terms of matroid data, and give conditions for hyperplane splits of matroid base polytopes. Also, we show how the cd-index of a polytope can be expressed when a polytope is split by a hyperplane, and apply these to the cd-index of a matroid base polytope of a rank 2 matroid.

math.CO↗

arXiv2008

Shellable complexes and topology of diagonal arrangements

We prove that if a simplicial complex is shellable, then the intersection lattice for the corresponding diagonal arrangement is homotopy equivalent to a wedge of spheres. Furthermore, we describe precisely the spheres in the wedge, based on the data of shelling. Also, we give some examples of diagonal arrangements where the complement is K(π,1), coming from rank 3 matroids.

math.CO↗