Graph isomorphism for (H1,H2)-free graphs: an almost complete dichotomy (2020)
Journal Article
Bonamy, M., Bousquet, N., Dabrowski, K., Johnson, M., Paulusma, D., & Pierron, T. (2021). Graph isomorphism for (H1,H2)-free graphs: an almost complete dichotomy. Algorithmica, 83(3), 822-852. https://doi.org/10.1007/s00453-020-00747-x

We resolve the computational complexity of GRAPH ISOMORPHISM for classes of graphs characterized by two forbidden induced subgraphs H_{1} and H_2 for all but six pairs (H_1,H_2). Schweitzer had previously shown that the number of open cases was finit... Read More about Graph isomorphism for (H1,H2)-free graphs: an almost complete dichotomy.

Disconnected cuts in claw-free graphs (2020)
Journal Article
Martin, B., Paulusma, D., & van Leeuwen, E. (2020). Disconnected cuts in claw-free graphs. Journal of Computer and System Sciences, 113, 60-75. https://doi.org/10.1016/j.jcss.2020.04.005

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. This problem is known to be NP-hard on general graphs. We prove that it is polyno... Read More about Disconnected cuts in claw-free graphs.

Clique-width for graph classes closed under complementation (2020)
Journal Article
Blanché, A., Dabrowski, K., Johnson, M., Lozin, V., Paulusma, D., & Zamaraev, V. (2020). Clique-width for graph classes closed under complementation. SIAM Journal on Discrete Mathematics, 34(2), 1107-1147. https://doi.org/10.1137/18m1235016

Clique-width is an important graph parameter due to its algorithmic and structural properties. A graph class is hereditary if it can be characterized by a (not necessarily finite) set H of forbidden induced subgraphs. We study the boundedness of cliq... Read More about Clique-width for graph classes closed under complementation.

Colouring (Pr + Ps)-Free Graphs (2020)
Journal Article
Klimošová, T., Malík, J., Masařík, T., Novotná, J., Paulusma, D., & Slívová, V. (2020). Colouring (Pr + Ps)-Free Graphs. Algorithmica, 82(7), 1833-1858. https://doi.org/10.1007/s00453-020-00675-w

The k-Colouring problem is to decide if the vertices of a graph can be coloured with at most k colours for a fixed integer k such that no two adjacent vertices are coloured alike. If each vertex u must be assigned a colour from a prescribed list L(u)... Read More about Colouring (Pr + Ps)-Free Graphs.

On Cycle Transversals and Their Connected Variants in the Absence of a Small Linear Forest (2020)
Journal Article
Dabrowski, K., Feghali, C., Johnson, M., Paesani, G., Paulusma, D., & Rzążewski, P. (2020). On Cycle Transversals and Their Connected Variants in the Absence of a Small Linear Forest. Algorithmica, 82(10), 2841-2866. https://doi.org/10.1007/s00453-020-00706-6

A graph is H-free if it contains no induced subgraph isomorphic to H. We prove new complexity results for the two classical cycle transversal problems FEEDBACK VERTEX SET and ODD CYCLE TRANSVERSAL by showing that they can be solved in polynomial time... Read More about On Cycle Transversals and Their Connected Variants in the Absence of a Small Linear Forest.