collaborators

8 papers

math.CO2026

Fatness and Flatness

Arnold Filtser, Hung Le, Nikolas Mählmann +2

Fat minors are the metric analog of graph minors that are tailored to the analysis of metric (edge-weighted) graphs and, more generally, metric spaces having a suitable notion of s…

math.CO2026

Hereditary 2-WQO Graph Classes Have Bounded Clique-Width

Julien Duron, Nikolas Mählmann, Szymon Toruńczyk

A graph class is -WQO if its -labeled graphs are well-quasi-ordered under label-preserving induced subgraph embeddings. We show that every hereditary graph class that is -…

cs.LO2026

A Note on Constructive Canonical Splitter Strategies in Nowhere Dense Graph Classes

Janne Fuchser, Nikolas Mählmann, Sebastian Siebertz

The radius- splitter game is played on a graph between two players: Splitter and Connector. In each round, Connector selects a vertex , and the current game arena is rest…

math.CO2026

Flips and Merge-Width in Sparse Graphs

Karolina Drabik, Maël Dumas, Nikolas Mählmann +2

A flip of a graph is obtained by complementing the edge relation within a set of vertices. Flips are typically used to separate vertices in a graph, by increasing the distances bet…

cs.CC2026

The Parameterized Complexity of Independent Set and More when Excluding a Half-Graph, Co-Matching, or Matching

Jan Dreier, Nikolas Mählmann, Sebastian Siebertz

A theorem of Ding, Oporowski, Oxley, and Vertigan implies that any sufficiently large twin-free graph contains a large matching, a co-matching, or a half-graph as a semi-induced su…

cs.DM2026

Existential Positive Transductions of Sparse Graphs

Nikolas Mählmann, Sebastian Siebertz

Monadic stability generalizes many tameness notions from structural graph theory such as planarity, bounded degree, bounded tree-width, and nowhere density. The sparsification conj…