Flow polytopes and the Kostant partition function

Autor: Karola Mészáros, Alejandro H. Morales
Jazyk: angličtina
Rok vydání: 2012
Předmět:
Zdroj: Discrete Mathematics & Theoretical Computer Science, Vol DMTCS Proceedings vol. AR,..., Iss Proceedings (2012)
Druh dokumentu: article
ISSN: 1365-8050
DOI: 10.46298/dmtcs.3096
Popis: We establish the relationship between volumes of flow polytopes associated to signed graphs and the Kostant partition function. A special case of this relationship, namely, when the graphs are signless, has been studied in detail by Baldoni and Vergne using techniques of residues. In contrast with their approach, we provide combinatorial proofs inspired by the work of Postnikov and Stanley on flow polytopes. As an application of our results we study a distinguished family of flow polytopes: the Chan-Robbins-Yuen polytopes. Inspired by their beautiful volume formula $\prod_{k=0}^{n-2} Cat(k)$ for the type $A_n$ case, where $Cat(k)$ is the $k^{th}$ Catalan number, we introduce type $C_{n+1}$ and $D_{n+1}$ Chan-Robbins-Yuen polytopes along with intriguing conjectures about their volumes.
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