Outputs (16)

Surjective H-colouring: New hardness results (2018)
Journal Article
Golovach, P., Johnson, M., Martin, B., Paulusma, D., & Stewart, A. (2019). Surjective H-colouring: New hardness results. Computability, 8(1), 27-42. https://doi.org/10.3233/com-180084

A homomorphism from a graph G to a graph H is a vertex mapping f from the vertex set of G to the vertex set of H such that there is an edge between vertices f(u) and f(v) of H whenever there is an edge between vertices u and v of G. The H-Colouring p... Read More about Surjective H-colouring: New hardness results.

On colouring (2P2,H)-free and (P5,H)-free graphs (2018)
Journal Article
Dabrowski, K., & Paulusma, D. (2018). On colouring (2P2,H)-free and (P5,H)-free graphs. Information Processing Letters, 134, 35-41. https://doi.org/10.1016/j.ipl.2018.02.003

The Colouring problem asks whether the vertices of a graph can be coloured with at most k colours for a given integer k in such a way that no two adjacent vertices receive the same colour. A graph is (H1,H2)-free if it has no induced subgraph isomorp... Read More about On colouring (2P2,H)-free and (P5,H)-free graphs.

Surjective H-Colouring over Reflexive Digraphs (2018)
Presentation / Conference Contribution
Larose, B., Martin, B., & Paulusma, D. (2023, February). Surjective H-Colouring over Reflexive Digraphs. Presented at 35th Symposium on Theoretical Aspects of Computer Science (STACS 2018), Caen, France

The Surjective H-Colouring problem is to test if a given graph allows a vertex-surjective homomorphism to a fixed graph H. The complexity of this problem has been well studied for undirected (partially) reflexive graphs. We introduce endo-triviality,... Read More about Surjective H-Colouring over Reflexive Digraphs.

Colouring Square-Free Graphs without Long Induced Paths (2018)
Presentation / Conference Contribution
Gaspers, S., Huang, S., & Paulusma, D. (2023, February). Colouring Square-Free Graphs without Long Induced Paths. Presented at 35th Symposium on Theoretical Aspects of Computer Science (STACS 2018), Caen, France

The Colouring problem is to decide if the vertices of a graph can be coloured with at most k colours for a given integer k such that no two adjacent vertices are coloured alike. The complexity of Colouring is fully understood for graph classes charac... Read More about Colouring Square-Free Graphs without Long Induced Paths.

Disconnected Cuts in Claw-free Graphs (2018)
Presentation / Conference Contribution
Martin, B., Paulusma, D., & van Leeuwen, E. J. (2018, August). Disconnected Cuts in Claw-free Graphs. Presented at 26th Annual European Symposium on Algorithms (ESA 2018)., Helsinki, Finland

A disconnected cut of a connected graph is a vertex cut that itself also induces a disconnected subgraph. The corresponding decision problem is called Disconnected Cut. It is known that Disconnected Cut is NP-hard on general graphs, while polynomial-... Read More about Disconnected Cuts in Claw-free Graphs.

On the price of independence for vertex cover, feedback vertex set and odd cycle transversal (2018)
Presentation / Conference Contribution
Dabrowski, K. K., Johnson, M., Paesani, G., Paulusma, D., & Zamaraev, V. (2018, August). On the price of independence for vertex cover, feedback vertex set and odd cycle transversal. Presented at 43nd International Symposium on Mathematical Foundations of Computer Science (MFCS 2018)., Liverpool, UK

Let vc(G), fvs(G) and oct(G) denote, respectively, the size of a minimum vertex cover, minimum feedback vertex set and minimum odd cycle transversal in a graph G. One can ask, when looking for these sets in a graph, how much bigger might they be if w... Read More about On the price of independence for vertex cover, feedback vertex set and odd cycle transversal.