Journal articleEnumerative Combinatorics and Applications · January 1, 2022
Let Pn be the convex hull in Rn of all parking functions of length n. Stanley found the number of vertices and the number of facets of Pn. Building upon these results, we determine the number of faces of arbitrary dimension ...
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Journal articleDiscrete Mathematics · January 1, 2020
The Wiener polynomial of a connected graph G is the polynomial W(G;x)=∑i=1D(G)di(G)xi where D(G) is the diameter of G, and di(G) is the number of pairs of vertices of G at distance i from each other. ...
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Journal articleJournal of Combinatorial Theory Series A · July 1, 2019
Let I n and J n denote the set of involutions and fixed-point free involutions of {1,…,n}, respectively, and let des(π) denote the number of descents of the permutation π. We prove a conjecture of Guo and Zeng which states that I
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Journal articleDiscrete Mathematics · April 1, 2019
For an abelian group G and an integer t>0, the modified Erdös–Ginzburg–Ziv constant st′(G) is the smallest integer ℓ such that any zero-sum sequence of length at least ℓ with elements in G contains a zero-sum subsequence (not necessa ...
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