activity
19932024
most citedA relative of Hadwiger's conjecture

34 citations · 188 across the 74 of their papers we have counts for

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Showing 2017 · math.COShow all

11 papers · 2 filters

math.CO2017

Induced subgraphs of graphs with large chromatic number. XII. Distant stars

Maria Chudnovsky, Alex Scott, Paul Seymour

The Gyarfas-Sumner conjecture asserts that if H is a tree then every graph with bounded clique number and very large chromatic number contains H as an induced subgraph. This is sti…

math.CO2017

Induced subgraphs of graphs with large chromatic number. XI. Orientations

Maria Chudnovsky, Alex Scott, Paul Seymour

Fix an oriented graph H, and let G be a graph with bounded clique number and very large chromatic number. If we somehow orient its edges, must there be an induced subdigraph isomor…

math.CO2017

Near-domination in graphs

Bruce Reed, Alex Scott, Paul Seymour

A vertex u of a graph t-dominates a vertex v if there are at most t vertices different from u,v that are adjacent to v and not to u; and a graph is t-dominating if for every pair o…

math.CO2017★ 14 cited

Clustered Colouring in Minor-Closed Classes

Sergey Norin, Alex Scott, Paul Seymour +1

The "clustered chromatic number" of a class of graphs is the minimum integer such that for some integer every graph in the class is -colourable with monochromatic compon…

math.CO2017★ 4 cited

Colouring perfect graphs with bounded clique number

Maria Chudnovsky, Aurélie Lagoutte, Paul Seymour +1

A graph is perfect if the chromatic number of every induced subgraph equals the size of its largest clique, and an algorithm of Grötschel, Lovász, and Schrijver from 1988 finds an…

math.CO2017★ 4 cited

Bad News for Chordal Partitions

Alex Scott, Paul Seymour, David R. Wood

Reed and Seymour [1998] asked whether every graph has a partition into induced connected non-empty bipartite subgraphs such that the quotient graph is chordal. If true, this would…

math.CO2017

Induced subgraphs of graphs with large chromatic number. X. Holes of specific residue

Alex Scott, Paul Seymour

A large body of research in graph theory concerns the induced subgraphs of graphs with large chromatic number, and especially which induced cycles must occur. In this paper, we uni…

math.CO2017

Induced subgraphs of graphs with large chromatic number. IX. Rainbow paths

Alex Scott, Paul Seymour

We prove that for all nonnegative integers k,s there exists c with the following property. Let G be a graph with clique number at most k and chromatic number more than c. Then for…

math.CO2017

Induced subgraphs of graphs with large chromatic number. VIII. Long odd holes

Maria Chudnovsky, Alex Scott, Paul Seymour +1

We prove a conjecture of Andras Gyarfas, that for all k,t, every graph with clique number at most k and sufficiently large chromatic number has an odd hole of length at least t.

math.CO2017

Induced subgraphs of graphs with large chromatic number. VII. Gyárfás' complementation conjecture

Alex Scott, Paul Seymour

A class of graphs is -bounded if there is a function such that for every induced subgraph of every graph in the class, where denote the chromatic…

math.CO2017

Induced subgraphs of graphs with large chromatic number. VI. Banana trees

Alex Scott, Paul Seymour

We investigate which graphs H have the property that in every graph with bounded clique number and sufficiently large chromatic number, some induced subgraph is isomorphic to a sub…