M. Siggers

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3 papers · 1 filter

math.CO2025

Obstructions for homomorphisms to odd cycles in series-parallel graphs

Eun-Kyung Cho, Ilkyoo Choi, Boram Park +1

For a graph $H$ , an $H$ -colouring of a graph $G$ is a vertex map $I ¨ : V (G) \to V (H)$ such that adjacent vertices are mapped to adjacent vertices. A graph $G$ is $C_{2 k + 1}$ -critical…

math.CO2025

The complexity of matroid homomorphism reconfiguration

Cheolwon Heo, Mark Siggers

We consider a reconfiguration version of the homomorphism problem $Hom_{M} (N)$ for binary matroids $N$ . This reconfiguration problem, $Recol_{M} (N)$ , asks…

math.CO2025

Reflexive Digraph Reconfiguration by Orientation Strings

David Emmanuel PazmiÃ±o Pullas, Mark Siggers

The reconfiguration problem for homomorphisms of digraphs to a reflexive digraph cycle, which amounts to deciding if a `reconfiguration graph' is connected, is known to by polynomi…