Flagged (P,ρ) -partitions
Flagged (P,ρ) -partitions
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标记 (P,Ï) - 分区
DOI:
10.1016/j.ejc.2020.103085
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发表时间:
2020
影响因子:
1
通讯作者:
Bergeron, Nantel
中科院分区:
文献类型:
--
作者:
Assaf, Sami;Bergeron, Nantel
We introduce the theory of (P, ρ)-partitions, depending on a poset P and a map ρ from P to positive integers. The generating function F P, ρ of (P, ρ)-partitions is a polynomial that, when the images of ρ tend to infinity, tends to Stanley’s generating function of P-partitions. Analogous to Stanley’s fundamental theorem for P-partitions, we show the set of (P, ρ)-partitions decomposes as a disjoint union of (L, ρ)-partitions where L runs over the set of linear extensions of P. In this more general context, the set of all F L, ρ for linear orders L over determines a basis of polynomials. We thus introduce the notion of flagged (P, ρ)-partitions, and we prove the set of all F L, ρ for flagged (L, ρ)-partitions for linear orders L is precisely the fundamental slide basis of the polynomial ring, introduced by the first author and Searles. Our main theorem shows that any generating function F P, ρ of flagged (P, ρ)-partitions is a positive integer linear combination g slide polynomials. As applications, we give a new proof of positivity of the slide product and, motivating our nomenclature, we also prove flagged Schur functions are slide positive.