Jørgen Bang-Jensen

collaborators

6 papers

math.CO2026

Sparse spanning $k$ -strong oriented subdigraphs in split digraphs

Jia Zhou, Jørgen Bang-Jensen, Jin Yan

Jackson and Thomassen conjectured that every $2 k$ -strong digraph admits a spanning $k$ -strong oriented subdigraph [Ann. N. Y. Acad. Sci. 555 (1989) 402-412]. The conjecture holds f…

math.CO2026

Highly connected spanning oriented subdigraphs in generalizations of semicomplete digraphs

Jia Zhou, JÃ¸rgen Bang-Jensen, Tong Zhou +1

Let $k$ be a positive integer. Jackson and Thomassen conjectured in 1989 that there exists an integer function $f (k)$ such that every $f (k)$ -strong digraph admits a spanning $k$ -st…

math.CO2026

K-Arc-Strong Orientations Of Semicomplete Digraphs

Tong Zhou, JÃ¸rgen Bang-Jensen, Jia Zhou +1

Results by Jackson and Frank imply that every 2k-arc-strong digraph D contains a spanning k-arc-strong oriented subdigraph. This is best possible, even for very dense digraphs. A d…

math.CO2025

Making an oriented graph acyclic using inversions of bounded or prescribed size

JÃ¸rgen Bang-Jensen, FrÃ©dÃ©ric Havet, Florian HÃ¶rsch +3

Given an oriented graph $D$ , the inversion of a subset $X$ of vertices consists in reversing the orientation of all arcs with both endpoints in $X$ . When the subset $X$ is of size…

math.CO2025

Acyclic dichromatic number of oriented graphs

JÃ¸rgen Bang-Jensen, Lucas Picasarri-Arrieta, Anders Yeo

The dichromatic number $I ¨ (D)$ of a digraph $D = (V, A)$ is the minimum number of sets in a partition $V_{1}, \dots, V_{k}$ of $V$ into $k$ subsets so that the induced subdigraph $D[…

math.CO2025

On the $k$ -linkage problem for generalizations of semicomplete digraphs

Jia Zhou, JÃ¸rgen Bang-Jensen, Jin Yan

A directed graph (digraph) $D$ is $k$ -linked if $∣ D ∣ \geq 2 k$ , and for any $2 k$ distinct vertices $x_{1}, \dots, x_{k}, y_{1}, \dots, y_{k}$ of $D$ , there exist vertex-disjoi…

Sparse spanning k-strong oriented subdigraphs in split digraphs

Highly connected spanning oriented subdigraphs in generalizations of semicomplete digraphs

K-Arc-Strong Orientations Of Semicomplete Digraphs

Making an oriented graph acyclic using inversions of bounded or prescribed size

Acyclic dichromatic number of oriented graphs

On the k-linkage problem for generalizations of semicomplete digraphs

Sparse spanning $k$ -strong oriented subdigraphs in split digraphs

On the $k$ -linkage problem for generalizations of semicomplete digraphs