A noncommutative approach to the Schur positivity of chromatic symmetric functions

التفاصيل البيبلوغرافية
العنوان: A noncommutative approach to the Schur positivity of chromatic symmetric functions
المؤلفون: Thibon, Jean-Yves, Wang, David G. L.
سنة النشر: 2023
المجموعة: Mathematics
مصطلحات موضوعية: Mathematics - Combinatorics, 05E05, 05C05, 05A15
الوصف: We obtain the Schur positivity of spider graphs of the forms $S(a,2,1)$ and $S(a,4,1)$, which are considered to have the simpliest structures for which the Schur positivity was unknown. The proof outline has four steps. First, we find noncommutative analogs for the chromatic symmetric functions of the spider graphs $S(a,b,1)$. Secondly, we expand the analogs under the $\Lambda$- and $R$-bases, whose commutative images are the elementary and skew Schur symmetric functions, respectively. Thirdly, we recognize the Schur coefficients via the Littlewood--Richardson rule in terms of norms of multisets of Yamanouchi words. At last we establish the Schur positivity combinatorially together with the aid of computer assistance.
Comment: 26 pages, with an appendix of 6 pages
نوع الوثيقة: Working Paper
URL الوصول: http://arxiv.org/abs/2305.07858
رقم الأكسشن: edsarx.2305.07858
قاعدة البيانات: arXiv