activity
20122023
most citedTriangle-free intersection graphs of line segments with large chromatic number

67 citations · 180 across the 16 of their papers we have counts for

collaborators

24 papers

math.CO2023

Forcing the Wheel

Jędrzej Hodor, William T. Trotter

Over the past 10 years, there has been considerable interest in exploring questions connecting dimension for posets with graph theoretic properties of their cover graphs and order…

math.CO2023

Concepts of Dimension for Convex Geometries

Kolja Knauer, William T. Trotter

Let be a finite set. A family of subsets of is called a convex geometry with ground set if (1) ; (2) whenever ; and (3)…

math.CO2022★ 3 cited

Boolean dimension and dim-boundedness: Planar cover graph with a zero

Heather Smith Blake, Piotr Micek, William T. Trotter

In 1989, Nešetřil and Pudlák posed the following challenging question: Do planar posets have bounded Boolean dimension? We show that every poset with a planar cover graph and a uni…

math.CO2020

Random bipartite posets and extremal problems

Csaba Biró, Peter Hamburger, H. A. Kierstead +3

Previously, Erdős, Kierstead and Trotter investigated the dimension of random height~ partially ordered sets. Their research was motivated primarily by two goals: (1)~analyzing…

math.CO2019★ 1 cited

Dimension is polynomial in height for posets with planar cover graphs

Jakub Kozik, Piotr Micek, William T. Trotter

We show that height posets that have planar cover graphs have dimension . Previously, the best upper bound was . Planarity plays a key r…

math.CO2019

Planar Posets that are Accessible from Below Have Dimension at Most 6

Csaba Biró, Bartłomiej Bosek, Heather C. Smith +3

Planar posets can have arbitrarily large dimension. However, a planar poset of height has dimension at most , while a planar poset with minimal elements has dimens…

math.CO2019

Fractional Local Dimension

Heather C. Smith, William T. Trotter

The original notion of dimension for posets was introduced by Dushnik and Miller in 1941 and has been studied extensively in the literature. In 1992, Brightwell and Scheinerman dev…

math.CO2018

Boolean Dimension, Components and Blocks

Tamás Mészáros, Piotr Micek, William T. Trotter

We investigate the behavior of Boolean dimension with respect to components and blocks. To put our results in context, we note that for Dushnik-Miller dimension, we have that if $\…

math.CO2017

Local Dimension is Unbounded for Planar Posets

Bartłomiej Bosek, Jarosław Grytczuk, William T. Trotter

In 1981, Kelly showed that planar posets can have arbitrarily large dimension. However, the posets in Kelly's example have bounded Boolean dimension and bounded local dimension, le…

math.CO2017

Comparing Dushnik-Miller Dimension, Boolean Dimension and Local Dimension

Fidel Barrera-Cruz, Thomas Prag, Heather Smith +2

The original notion of dimension for posets is due to Dushnik and Miller and has been studied extensively in the literature. Quite recently, there has been considerable interest in…

math.CO2017

The Graph of Critical Pairs of a Crown

Fidel Barrera-Cruz, Rebecca Garcia, Pamela Harris +5

There is a natural way to associate with a poset a hypergraph , called the hypergraph of critical pairs, so that the dimension of is exactly equal to the chromatic numbe…

math.CO2017

Boolean dimension and local dimension

William T. Trotter, Bartosz Walczak

Dimension is a standard and well-studied measure of complexity of posets. Recent research has provided many new upper bounds on the dimension for various structurally restricted cl…

math.CO2017★ 1 cited

Burling graphs, chromatic number, and orthogonal tree-decompositions

Stefan Felsner, Gwenaël Joret, Piotr Micek +2

A classic result of Asplund and Grünbaum states that intersection graphs of axis-aligned rectangles in the plane are -bounded. This theorem can be equivalently stated in terms o…

math.CO2017

Separating Tree-chromatic number from Path-chromatic Number

Fidel Barrera-Cruz, Stefan Felsner, Tamás Mészáros +4

We apply Ramsey theoretic tools to show that there is a family of graphs which have tree-chromatic number at most~ while the path-chromatic number is unbounded. This resolves a…

math.CO2016★ 9 cited

Dimension of posets with planar cover graphs excluding two long incomparable chains

David M. Howard, Noah Streib, William T. Trotter +2

It has been known for more than 40 years that there are posets with planar cover graphs and arbitrarily large dimension. Recently, Streib and Trotter proved that such posets must h…

math.CO2015★ 23 cited

First-fit coloring on interval graphs has performance ratio at least 5

H. A. Kierstead, David A. Smith, W. T. Trotter

First-fit is the online graph coloring algorithm that considers vertices one at a time in some order and assigns each vertex the least positive integer not used already on a neighb…

math.CO2015★ 12 cited

Dimension and cut vertices: an application of Ramsey theory

William T. Trotter, Bartosz Walczak, Ruidong Wang

Motivated by quite recent research involving the relationship between the dimension of a poset and graph-theoretic properties of its cover graph, we show that for every ,…

math.CO2014

On the dimension of posets with cover graphs of treewidth

Gwenaël Joret, Piotr Micek, William T. Trotter +2

In 1977, Trotter and Moore proved that a poset has dimension at most whenever its cover graph is a forest, or equivalently, has treewidth at most . On the other hand, a well…

math.CO2014★ 1 cited

Forcing Posets with Large Dimension to Contain Large Standard Examples

Csaba Biró, Peter Hamburger, Attila Pór +1

The dimension of a poset , denoted , is the least positive integer for which is the intersection of linear extensions of . The maximum dimension of a pos…

math.CO2013

Incidence Posets and Cover Graphs

William T. Trotter, Ruidong Wang

We prove two theorems concerning incidence posets of graphs, cover graphs of posets and a related graph parameter. First, answering a question of Haxell, we show that the chromatic…

math.CO2013★ 25 cited

Tree-width and dimension

Gwenaël Joret, Piotr Micek, Kevin G. Milans +3

Over the last 30 years, researchers have investigated connections between dimension for posets and planarity for graphs. Here we extend this line of research to the structural grap…

math.CO2012★ 36 cited

Triangle-free geometric intersection graphs with large chromatic number

Arkadiusz Pawlik, Jakub Kozik, Tomasz Krawczyk +4

Several classical constructions illustrate the fact that the chromatic number of a graph can be arbitrarily large compared to its clique number. However, until very recently, no su…

math.CO2012★ 67 cited

Triangle-free intersection graphs of line segments with large chromatic number

Arkadiusz Pawlik, Jakub Kozik, Tomasz Krawczyk +4

In the 1970s, Erdos asked whether the chromatic number of intersection graphs of line segments in the plane is bounded by a function of their clique number. We show the answer is n…

math.CO2012★ 2 cited

An extremal problem on crossing vectors

Michał Lasoń, Piotr Micek, Noah Streib +2

For positive integers and , two vectors and from are called -crossing if there are two coordinates and such that and $B[j…