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Richard P. Stanley defined the chromatic symmetric function of a simple graph and has conjectured that every tree is determined by its chromatic symmetric function. Recently, Takahiro Hasebe and the author proved that the order…

Combinatorics · Mathematics 2018-07-23 Shuhei Tsujie

We explore several generalizations of Whitney's theorem -- a classical formula for the chromatic polynomial of a graph. Following Stanley, we replace the chromatic polynomial by the chromatic symmetric function. Following Dohmen and Trinks,…

Combinatorics · Mathematics 2023-05-08 Darij Grinberg

We study the $H$-chromatic symmetric functions $X_G^H$ (introduced in (arXiv:2011.06063) as a generalization of the chromatic symmetric function (CSF) $X_G$), which track homomorphisms from the graph $G$ to the graph $H$. We focus first on…

Combinatorics · Mathematics 2025-11-13 Shao Yuan Lin , Laura Pierson

The chromatic polynomial $P(G,x)$ of a graph $G$ of order $n$ can be expressed as $\sum\limits_{i=1}^n(-1)^{n-i}a_{i}x^i$, where $a_i$ is interpreted as the number of broken-cycle free spanning subgraphs of $G$ with exactly $i$ components.…

Combinatorics · Mathematics 2020-08-12 Fengming Dong , Jun Ge , Helin Gong , Bo Ning , Zhangdong Ouyang , Eng Guan Tay

For each indifference graph, there is an associated regular semisimple Hessenberg variety, whose cohomology recovers the chromatic symmetric function of the graph. The decomposition theorem applied to the forgetful map from the regular…

Algebraic Geometry · Mathematics 2023-04-24 Alex Abreu , Antonio Nigro

Cylindric skew Schur functions, a generalization of skew Schur functions, are closely related to the famous problem finding a combinatorial formula for the 3-point Gromov-Witten invariants of Grassmannian. In this paper, we prove cylindric…

Combinatorics · Mathematics 2017-06-15 Seung Jin Lee

The generalised colouring numbers $\mathrm{adm}_r(G)$, $\mathrm{col}_r(G)$, and $\mathrm{wcol}_r(G)$ were introduced by Kierstead and Yang as generalisations of the usual colouring number, also known as the degeneracy of a graph, and have…

Discrete Mathematics · Computer Science 2016-06-30 Stephan Kreutzer , Michał Pilipczuk , Roman Rabinovich , Sebastian Siebertz

We introduce a quasisymmetric class function associated with a group acting on a double poset or on a directed graph. The latter is a generalization of the chromatic quasisymmetric function of a digraph introduced by Ellzey, while the…

Combinatorics · Mathematics 2021-06-08 Jacob A White

We study a linear map on symmetric functions that ``divides'' a partition by a positive integer $k$, sending a Schur function indexed by a partition of $kn$ to a symmetric function indexed by partitions of $n$. We determine its Schur…

Combinatorics · Mathematics 2026-05-22 Per Alexandersson , Lilan Dai

We introduce a basis of the symmetric functions that evaluates to the (irreducible) characters of the symmetric group, just as the Schur functions evaluate to the irreducible characters of $GL_n$ modules. Our main result gives three…

Combinatorics · Mathematics 2021-08-10 Rosa Orellana , Mike Zabrocki

We introduce and study a family of inhomogeneous symmetric functions which we call the Frobenius-Schur functions. These functions are indexed by partitions and differ from the conventional Schur functions in lower terms only. Our interest…

Combinatorics · Mathematics 2007-05-23 Grigori Olshanski , Amitai Regev , Anatoly Vershik

We prove a new signed elementary symmetric function expansion of the chromatic quasisymmetric function of any natural unit interval graph. We then use a sign-reversing involution to prove a new combinatorial formula for K-chains, which are…

Combinatorics · Mathematics 2024-05-09 Foster Tom

In this work, we generalize and utilize the linear relations of LLT polynomials introduced by Lee \cite{Lee}. By using the fact that the chromatic quasisymmetric functions and the unicellular LLT polynomials are related via plethystic…

Combinatorics · Mathematics 2018-12-11 JiSun Huh , Sun-Young Nam , Meesue Yoo

The involution Stanley symmetric functions $\hat{F}_y$ are the stable limits of the analogues of Schubert polynomials for the orbits of the orthogonal group in the flag variety. These symmetric functions are also generating functions for…

Combinatorics · Mathematics 2017-11-10 Zachary Hamaker , Eric Marberg , Brendan Pawlowski

We describe a combinatorial formula for the coefficients when the dual immaculate quasisymmetric functions are decomposed into Young quasisymmetric Schur functions. We prove this using an analogue of Schensted insertion. Using this result,…

Combinatorics · Mathematics 2016-06-14 Edward E. Allen , Joshua Hallam , Sarah K. Mason

Stanley asked whether a tree is determined up to isomorphism by its chromatic symmetric function. We approach Stanley's problem by studying the relationship between the chromatic symmetric function and other invariants. First, we prove…

Combinatorics · Mathematics 2024-07-24 José Aliste-Prieto , Jeremy L. Martin , Jennifer D. Wagner , José Zamora

The irreducible characters of the symmetric group are a symmetric polynomial in the eigenvalues of a permutation matrix. They can therefore be realized as a symmetric function that can be evaluated at a set of variables and form a basis of…

Combinatorics · Mathematics 2016-06-19 Rosa Orellana , Mike Zabrocki

In work with A. Yong, the author introduced genomic tableaux to prove the first positive combinatorial rule for the Littlewood-Richardson coefficients in torus-equivariant $K$-theory of Grassmannians. We then studied the genomic Schur…

Combinatorics · Mathematics 2022-03-25 Oliver Pechenik

The $e$-positivity conjecture and the $e$-unimodality conjecture of chromatic quasisymmetric functions are proved for some classes of natural unit interval orders. Recently, J. Shareshian and M. Wachs introduced chromatic quasisymmetric…

Combinatorics · Mathematics 2017-11-28 Soojin Cho , JiSun Huh

We study the symmetric function and polynomial combinatorial invariants of Hopf algebras of permutations, posets and graphs. We investigate their properties and the relations among them. In particular, we show that the chromatic symmetric…

Combinatorics · Mathematics 2020-10-01 Jean-christophe Aval , Nantel Bergeron , John Machacek