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Link to original content: https://doi.org/10.7151/dmgt.2442
DMGT

DMGT

ISSN 1234-3099 (print version)

ISSN 2083-5892 (electronic version)

https://doi.org/10.7151/dmgt

Discussiones Mathematicae Graph Theory

Journal Impact Factor (JIF 2023): 0.5

5-year Journal Impact Factor (2023): 0.6

CiteScore (2023): 2.2

SNIP (2023): 0.681

Discussiones Mathematicae Graph Theory

Article in volume


Authors:

R. Wang

Ruixia Wang

shanxi university

email: wangrx@sxu.edu.cn

0000-0001-9965-0449

L. Wu

Linxin Wu

shanxi university

email: lswwrx@163.com

Title:

Cycles of many lengths in balanced bipartite digraphs on dominating and dominated degree conditions

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Source:

Discussiones Mathematicae Graph Theory 44(1) (2024) 245-267

Received: 2021-07-15 , Revised: 2021-11-29 , Accepted: 2021-11-29 , Available online: 2021-12-14 , https://doi.org/10.7151/dmgt.2442

Abstract:

In 2017, Adamus proved that a strong balanced bipartite digraph of order $2a$ with $a\geq 3$ is hamiltonian, if $d(u)+d(v)\geq 3a$ for every pair of dominating or dominated vertices $\{u,v\}$. In this paper, we characterize all non-hamiltonian bipartite digraphs when $d(u)+d(v)\geq 3a-1$ for every pair of dominating or dominated vertices $\{u,v\}$, consisting of one infinite family and four exceptional bipartite digraphs of order six. Using this result, we also prove that a strong balanced bipartite digraph of order $2a$ with $a\geq 4$ contains all cycles of lengths $2, 4, \ldots, 2a-2$ except for a single bipartite digraph, and also contains a hamiltonian path, if $d(u)+d(v)\geq 3a-1$ for every pair of dominating or dominated vertices $\{u, v\}$. The bounds for $3a-1$ in two results are sharp. This partly settles the following problem when $l=a-1$ proposed by Adamus [A Meyniel-type condition for bipancyclicity in balanced bipartitie digraphs, Graphs Combin. 34 (2018) 703–709]. Whether for every $1\le l< a$ there is a $k(l)$, $k(l)\ge 1$, such that every strong balanced bipartite digraph of order $2a$ contains cycles of lengths $2, 4, \ldots, 2l$, whenever $d(u)+d(v)\ge 3a-k(l)$ for every pair of dominating or dominated vertices $\{u, v\}$.

Keywords:

bipartite digraph, degree sum, bipancyclicity, hamiltonian cycle

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