activity
20232026
collaborators

11 papers

math.CO2026

Hypergraphs with the smallest Hall ratio are still hard to colour

Veronica Bitonti, Freddie Illingworth, Pedram Noohi +1

For a hypergraph, the Hall ratio is a natural lower bound for its chromatic number, and among non-empty -u…

math.CO2026

Two Relaxations of the Dominating Hadwiger's Conjecture

António Girão, Sergey Norin, Youri Tamitegama +1

Illingworth and Wood recently proposed the Dominating Hadwiger's Conjecture, a strengthening of Hadwiger's Conjecture which asserts that every graph with no dominating -model…

math.CO2026

The Dominating 4-Colour Theorem

António Girão, Freddie Illingworth, Bojan Mohar +6

A "dominating -model" in a graph is a sequence of pairwise vertex-disjoint connected subgraphs of , such that whenever every vertex…

math.CO2026

Canonical labelling of random regular graphs

Mikhail Isaev, Tamás Makai, Brendan McKay +3

We prove that whenever and as , then with high probability for any non-trivial initial colouring, the colour refinement algorithm disti…

math.CO2025

Packing subdivisions into regular graphs

Richard Montgomery, Kalina Petrova, Arjun Ranganathan +1

We show that, for any graph and , there exists a such that every -vertex -regular graph with has a collection of vertex-disjoint -subd…

math.CO2025

A local limit theorem for the edge counts of random induced subgraphs of a random graph

Paul Balister, Emil Powierski, Alex Scott +1

Consider a `dense' Erdős--Rényi random graph model with vertices and edges, where we assume the edge density is bounded away from 0 and 1. Fix…

math.CO2025

Tight Bounds for Hypercube Minor-Universality

Emma Hogan, Lukas Michel, Alex Scott +3

Benjamini, Kalifa and Tzalik recently proved that there is an absolute constant such that any graph with at most edges and no isolated vertices is a minor of th…

math.CO2024

Clustered Colouring of Graph Products

Rutger Campbell, J. Pascal Gollin, Kevin Hendrey +5

A colouring of a graph has clustering if the maximum number of vertices in a monochromatic component equals . Motivated by recent results showing that many natural graph…

math.CO2024

When -intersecting hypergraphs admit bounded -strong colourings

Kevin Hendrey, Freddie Illingworth, Nina Kamčev +1

The -strong chromatic number of a hypergraph is the smallest number of colours needed to colour its vertices so that every edge sees at least colours or is rainbow. We show…

math.CO2024

A note on graphs of -colourings

Emma Hogan, Alex Scott, Youri Tamitegama +1

For a graph , the -colouring graph of has vertices corresponding to proper -colourings of and edges between colourings that differ at a single vertex. The graph su…

math.CO2023

Boundary rigidity of 3D CAT(0) cube complexes

John Haslegrave, Alex Scott, Youri Tamitegama +1

The boundary rigidity problem is a classical question from Riemannian geometry: if is a Riemannian manifold with smooth boundary, is the geometry of determined up to i…