activity
20142024
most citedTriangular Ladders are -positive

12 citations · 15 across the 8 of their papers we have counts for

collaborators

14 papers

math.CO2024

Maximal chains in lattices from graph associahedra: Tamari to the weak order

Samantha Dahlberg, Susanna Fishel

In this paper, we study the maximal chains of lattices which generalizes both the weak order and the Tamari lattice: certain lattices of maximal tubings. A maximal tubing poset $\m…

math.CO2023

A Polynomial Method for Counting Colorings of Sparse Graphs

Samantha L. Dahlberg, Hemanshu Kaul, Jeffrey A. Mudrock

The notion of -labeling of graphs, where is a subset of a symmetric group, was introduced in 2019 by Jin, Wong, and Zhu. This notion provides the framework for a common gene…

math.CO2022

An Algebraic Approach for Counting DP-3-colorings of Sparse Graphs

Samantha L. Dahlberg, Hemanshu Kaul, Jeffrey A. Mudrock

DP-coloring (or correspondence coloring) is a generalization of list coloring that has been widely studied since its introduction by Dvořák and Postle in 2015. As the analogue of t…

math.CO2020★ 1 cited

Diameters of Graphs on Reduced Words of 12 and 21-Inflations

Samantha Dahlberg, Younghwan Kim

It is a classical result that any permutation in the symmetric group can be generated by a sequence of adjacent transpositions. The sequences of minimal length are called reduced w…

math.CO2019

Chromatic Posets

Samantha Dahlberg, Adrian She, Stephanie van Willigenburg

In 1995 Stanley introduced the chromatic symmetric function of a graph , whose -positivity and Schur-positivity has been of large interest. In this paper we study the r…

math.CO2019

Chromatic symmetric functions in noncommuting variables revisited

Samantha Dahlberg, Stephanie van Willigenburg

In 1995 Stanley introduced a generalization of the chromatic polynomial of a graph , called the chromatic symmetric function, , which was generalized to noncommuting variab…

math.CO2019

Schur and -positivity of trees and cut vertices

Samantha Dahlberg, Adrian She, Stephanie van Willigenburg

We prove that the chromatic symmetric function of any -vertex tree containing a vertex of degree is not -positive, that is, not a positive linear combinat…

math.CO2018★ 12 cited

Triangular Ladders are -positive

Samantha Dahlberg

In 1995 Stanley conjectured that the chromatic symmetric functions of the graphs , which we call triangular ladders, were -positive. In this paper we confirm this conje…

math.CO2017★ 1 cited

Permutation Statistics and Pattern Avoidance in Involutions

Samantha Dahlberg

Dokos et. al. studied the distribution of two statistics over permutations of that avoid one or more length three patterns. A permutation $σ\in\…

math.CO2017

Resolving Stanley's -positivity of claw-contractible-free graphs

Samantha Dahlberg, Angele Foley, Stephanie van Willigenburg

In Stanley's seminal 1995 paper on the chromatic symmetric function, he stated that there was no known graph that was not contractible to the claw and whose chromatic symmetric fun…

math.CO2017

Lollipop and lariat symmetric functions

Samantha Dahlberg, Stephanie van Willigenburg

We compute an explicit -positive formula for the chromatic symmetric function of a lollipop graph, . From here we deduce that there exist countably infinite distinct $e…

math.CO2016

Restricted growth function patterns and statistics

Lindsey R. Campbell, Samantha Dahlberg, Robert Dorward +4

A restricted growth function (RGF) of length n is a sequence w = w_1 w_2 ... w_n of positive integers such that w_1 = 1 and w_i is at most 1 + max{w_1,..., w_{i-1}} for i at least…

math.CO2015★ 1 cited

Set partition patterns and statistics

Samantha Dahlberg, Robert Dorward, Jonathan Gerhard +4

A set partition of contains another set partition if restricting to some and then standardizing the result gives . Otherwise we s…

math.CO2014

Combinatorial Proofs of Identities Involving Symmetric Matrices

Samantha Dahlberg

Brualdi and Ma found a connection between involutions of length with descents and symmetric matrices with non-negative integer entries summing to and having…