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15 papers · 1 filter

math.CO2026

Paths with Prescribed Endpoints in Semicomplete and Locally Semicomplete Digraphs

Hanzhi Bai, Jin Yan, Jia Zhou

We study two open path problems with prescribed endpoints posed by Bang-Jensen and Gutin. The first asks for a longest -path in a semicomplete digraph. The second asks wheth…

math.CO2026

Ramsey--Turán Factors of Non-directed Oriented Cycles in Oriented Graphs

Jia Zhou, Yunshu Gao

Let be any orientation of the cycle which is not directed. We prove that, for every integer and every , there is a real such tha…

math.CO2026

Dominant-Degree Conditions for Ramsey--Turán Factors of Non-Directed Cycle Orientations

Jia Zhou, Yunshu Gao

Let $\Cvec$ be a fixed orientation of the cycle , , which is not directed. For an oriented graph , let and let \[ \sigor…

math.CO2026

A Chvátal--Erdős type condition for supereulerian digraphs with

Zirui Liu, Jin Yan, Jia Zhou

A digraph is \textbf{supereulerian} if it contains a spanning closed trail. Let denote the maximum cardinality of a vertex set inducing no 2-cycle. In this paper, we chara…

math.CO2026

Complexity of Arc-Decompositions involving Perfect Matchings and Cycle Factors

Hangning Liu, Jørgen Bang-Jensen, Jin Yan +1

For two digraph properties and , a -arc-decomposition of a digraph is a partition such that the spanning subdigraphs $D[A_…

math.CO2026

Sparse spanning -strong oriented subdigraphs in split digraphs

Jia Zhou, Jørgen Bang-Jensen, Jin Yan

Jackson and Thomassen conjectured that every -strong digraph admits a spanning -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, Jørgen Bang-Jensen, Tong Zhou +1

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

math.CO2026

K-Arc-Strong Orientations Of Semicomplete Digraphs

Tong Zhou, Jørgen 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.CO2026

On the 2-Linkage Problem for Split Digraphs

Xiaoying Chen, Jørgen Bang-Jensen, Jin Yan +1

A digraph is {\bf \( k \)-linked} if for arbitary two disjoint vertex sets \(\{s_1, \ldots, s_k\}\) and \(\{t_1, \ldots, t_k\}\), there exist vertex-disjoint directed paths \(P_1,…

math.CO2025

Proof of the linkage conjecture for highly connected tournaments

Jia Zhou, Jin Yan

A digraph is -linked if for every distinct vertices in , there exist pairwise vertex-disjoint paths such…

math.CO2025

On the -linkage problem for generalizations of semicomplete digraphs

Jia Zhou, Jørgen Bang-Jensen, Jin Yan

A directed graph (digraph) is -linked if , and for any distinct vertices of , there exist vertex-disjoi…

math.CO2024

Solutions to the linkage conjecture in tournaments

Jia Zhou, Jin Yan

A digraph is -linked if for every -tuple of distinct vertices in , there exist pairwise vertex-disjoint paths $P_1,\ldots,…

math.CO2024

Semi-Degree Condition for Arbitrary -Linked Oriented Graphs

Jia Zhou, Jin Yan

Let be a multi-digraph on vertices with arcs. An \textbf{-subdivision} in a digraph is a subdigraph obtained by replacing every arc of with a path…

math.CO2024

Bipartitions with prescribed order of highly connected digraphs

Yuzhen Qi, Jin Yan, Jia Zhou

A digraph is strongly connected if it has a directed path from to for every ordered pair of distinct vertices and it is strongly -connected if it has at least $k+…

math.CO2024

The generalizations of Hamiltonian in oriented graphs

Jia Zhou, Zhilan Wang, Jin Yan

An oriented graph is an orientation of a simple graph. In 2009, Keevash, Kühn and Osthus proved that every sufficiently large oriented graph of order with is Ham…