R. Thomas

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math.CO2024

Robertson's conjecture I. Well-quasi-ordering bounded tree-width graphs by the topological minor relation

Chun-Hung Liu, Robin Thomas

Robertson and Seymour's celebrated Graph Minor Theorem states that graphs are well-quasi-ordered by the minor relation. Unlike the minor relation, the topological minor relation do…

math.CO2024

Packing $A$ -paths of length zero modulo a prime

Robin Thomas, Youngho Yoo

It is known that $A$ -paths of length $0$ mod $m$ satisfy the ErdÅs-PÃ³sa property if $m = 2$ or $m = 4$ , but not if $m > 4$ is composite. We show that if $p$ is prime, then $A$ -paths…

math.CO2024

Packing cycles in undirected group-labelled graphs

Robin Thomas, Youngho Yoo

We prove a refinement of the flat wall theorem of Robertson and Seymour to undirected group-labelled graphs $(G, I^^{3})$ where $I^^{3}$ assigns to each edge of an undirected graph $G$ an e…

Robertson's conjecture I. Well-quasi-ordering bounded tree-width graphs by the topological minor relation

Packing A-paths of length zero modulo a prime

Packing cycles in undirected group-labelled graphs

Packing $A$ -paths of length zero modulo a prime