activity
20182025
most citedA Menger-type theorem for two induced paths

7 citations · 19 across the 19 of their papers we have counts for

collaborators

20 papers

math.CO2025

The global structure of locally chordal graphs

Tara Abrishami, Paul Knappe

A graph is locally chordal if each of its small-radius balls is chordal. In an earlier work [AKK25], the authors and Kobler proved that locally chordal graphs can be characterized…

math.CO2025

Locally interval graphs are circular-arc graphs

Tara Abrishami, Sandra Albrechtsen, Nathan Bowler +2

Circular-arc graphs are graphs that can be represented as intersection graphs of subpaths of a cycle. Interval graphs are graphs that can be represented as intersection graphs of s…

math.CO2025

Canonical tree-decompositions of chordal graphs

Raphael W. Jacobs, Paul Knappe

We show that a locally finite, connected graph is -locally chordal (that is, its -balls are chordal) if and only if the unique canonical graph-decomposition $\mathcal{H…

math.CO2025

Locally chordal graphs

Tara Abrishami, Paul Knappe, Jonas Kobler

In this paper we study locally chordal graphs, i.e. graphs where every small-radius ball is chordal. We prove four characterizations of locally chordal graphs. Two are counterparts…

math.CO2025

Canonical graph decompositions via local separations

Raphael W. Jacobs, Paul Knappe, Jan Kurkofka

Every finite graph can be decomposed in a canonical way that displays its local connectivity-structure [DJKK26]. These decompositions are defined via a suitable more tree-like…

math.CO2024

On vertex sets inducing tangles

Sandra Albrechtsen, Hanno von Bergen, Raphael W. Jacobs +2

Diestel, Hundertmark and Lemanczyk asked whether every -tangle in a graph is induced by a set of vertices by majority vote. We reduce their question to graphs whose size is boun…

math.CO2024

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.CO2024

A characterisation of graphs quasi-isometric to -minor-free graphs

Sandra Albrechtsen, Raphael W. Jacobs, Paul Knappe +1

We prove that there is a function such that every graph with no -fat minor is -quasi-isometric to a graph with no minor. This solves the -case of a ge…

math.CO2024★ 1 cited

Linked tree-decompositions into finite parts

Sandra Albrechtsen, Raphael W. Jacobs, Paul Knappe +1

We prove that every graph which admits a tree-decomposition into finite parts has a rooted tree-decomposition into finite parts that is linked, tight and componental. As an applica…

math.CO2024

Counterexamples regarding linked and lean tree-decompositions of infinite graphs

Sandra Albrechtsen, Raphael W. Jacobs, Paul Knappe +1

Kriz and Thomas showed that every (finite or infinite) graph of tree-width admits a lean tree-decomposition of width . We discuss a number of counterexamples…

math.CO2023

A structural duality for path-decompositions into parts of small radius

Sandra Albrechtsen, Reinhard Diestel, Ann-Kathrin Elm +4

It is an easy observation that if a graph~ admits a path-decomposition whose parts have small radius, then contains no large subdivision of or as a (quasi-)g…

math.CO2023★ 7 cited

A Menger-type theorem for two induced paths

Sandra Albrechtsen, Tony Huynh, Raphael W. Jacobs +2

We give an approximate Menger-type theorem for when a graph contains two paths and such that is an induced subgraph of . More generally, we…

math.CO2023★ 2 cited

Efficiently distinguishing all tangles in locally finite graphs

Raphael W. Jacobs, Paul Knappe

While finite graphs have tree-decompositions that efficiently distinguish all their tangles, locally finite graphs with thick ends need not have such tree-decompositions. We show t…

math.CO2023

A grid theorem for strong immersions of walls

Reinhard Diestel, Raphael W. Jacobs, Paul Knappe +1

We show that a graph contains a large wall as a strong immersion minor if and only if the graph does not admit a tree-cut decomposition of small 'width', which is measured in terms…

math.CO2022★ 3 cited

The immersion-minimal infinitely edge-connected graph

Paul Knappe, Jan Kurkofka

We show that there is a unique immersion-minimal infinitely edge-connected graph: every such graph contains the halved Farey graph, which is itself infinitely edge-connected, as an…

math.CO2022★ 2 cited

Canonical graph decompositions via coverings

Reinhard Diestel, Raphael W. Jacobs, Paul Knappe +1

We present a canonical way to decompose finite graphs into highly connected local parts. The decomposition depends only on an integer parameter whose choice sets the intended degre…

math.CO2021★ 1 cited

The Lovász-Cherkassky theorem for locally finite graphs with ends

Raphael W. Jacobs, Attila Joó, Paul Knappe +2

Lovász and Cherkassky discovered independently that, if is a finite graph and such that the degree is even for every vertex , t…

math.CO2019★ 1 cited

Base partition for mixed families of finitary and cofinitary matroids

Joshua Erde, Pascal Gollin, Attila Joó +2

Let be a finite or infinite family consisting of matroids on a common ground set each of which may be finitary or cofinitary. We prove the…

math.CO2019★ 2 cited

A Cantor-Bernstein-type theorem for spanning trees in infinite graphs

Joshua Erde, Pascal Gollin, Atilla Joó +2

We show that if a graph admits a packing and a covering both consisting of many spanning trees, where is some infinite cardinal, then the graph also admits a decomposition…

math.CO2018

Circuits through prescribed edges

Paul Knappe, Max Pitz

We prove that a connected graph contains a circuit---a closed walk that repeats no edges---through any prescribed edges if and only if it contains no odd cut of size at most $k…