activity
20232026
most citedA Menger-type theorem for two induced paths

7 citations · 11 across the 11 of their papers we have counts for

collaborators

13 papers

math.CO2026

Proof of Lichiardopol's conjecture on disjoint directed cycles of distinct lengths

Sandra Albrechtsen, Raphael Steiner

There is a fascinating array of interrelated questions studying which structures can be guaranteed in digraphs of large minimum out-degree. These often have intriguingly simple sta…

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

Displaying prescribed sets of ends by linked tree-decompositions

Sandra Albrechtsen, Max Pitz, Roman Schaut

We show that if a subset of the ends of a graph can be displayed by a tree-decomposition of finite adhesion, then it can also be displayed by a linked such tree-decompositi…

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

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

Tangle-tree duality in infinite graphs

Sandra Albrechtsen

We extend Robertson and Seymour's tangle-tree duality theorem to infinite graphs.

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.CO2024

Refining tree-decompositions so that they display the k-blocks

Sandra Albrechtsen

Carmesin and Gollin proved that every finite graph has a canonical tree-decomposition of adhesion less than that efficiently distinguishes every two distinct…

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★ 1 cited

Optimal trees of tangles: refining the essential parts

Sandra Albrechtsen

We combine the two fundamental fixed-order tangle theorems of Robertson and Seymour into a single theorem that implies both, in a best possible way. We show that, for every $k \in…

math.CO2023★ 2 cited

Refining trees of tangles in abstract separation systems: inessential parts

Sandra Albrechtsen

Robertson and Seymour proved two fundamental theorems about tangles in graphs: the tree-of-tangles theorem, which says that every graph has a tree-decomposition such that distingui…