3 papers
math.CO2026
Infinite grids in digraphs
Matthias Hamann, Karl Heuer
Halin proved that every graph with an end containing infinitely many pairwise disjoint rays admits a subdivision of the infinite quarter-grid as a subgraph where all rays from…
math.CO2025
Periodic colorings and orientations in infinite graphs
Tara Abrishami, Louis Esperet, Ugo Giocanti +3
We study the existence of periodic colorings and orientations in locally finite graphs. A coloring or orientation of a graph is periodic if the resulting colored or oriented gr…
math.CO2025
An end degree for digraphs
Matthias Hamann, Karl Heuer
In this paper we define a degree for ends of infinite digraphs. The well-definedness of our definition in particular resolves a problem by Zuther. Furthermore, we extend our notion…