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Related papers: Thick weakly distance-regular digraphs

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A weakly distance-regular digraph is 3-equivalenced if its attached association scheme is 3-equivalenced. In this paper, we classify the family of such digraphs under the assumption of the commutativity.

Combinatorics · Mathematics 2017-08-01 Yuefeng Yang , Benjian Lv , Kaishun Wang

A weakly distance-regular digraph is $P$-polynomial if its attached scheme is $P$-polynomial. In this paper, we characterize all $P$-polynomial weakly distance-regular digraphs.

Combinatorics · Mathematics 2023-06-28 Qing Zeng , Yuefeng Yang , Kaishun Wang

A weakly distance-regular digraph is quasi-thin if the maximum value of its intersection numbers is 2. In this paper, we focus on commutative quasi-thin weakly distance-regular digraphs, and classify such digraphs with valency more than 3.…

Combinatorics · Mathematics 2018-10-01 Yuefeng Yang , Benjian Lv , Kaishun Wang

In this paper, we study commutative weakly distance-regular digraphs whose attached association schemes are regular, and give a characterization of mixed arcs. As an application, we classify such digraphs of diameter 2.

Combinatorics · Mathematics 2020-03-20 Yuefeng Yang , Benjian Lv , Kaishun Wang

Weakly distance-regular digraphs are a natural directed version of distance-regular graphs. In [8], the third author and Suzuki proposed a question when an orientation of a distance-regular graph defines a weakly distance-regular digraph.…

Combinatorics · Mathematics 2024-04-11 Yuefeng Yang , Qing Zeng , Kaishun Wang

Weakly distance-regular digraphs is a directed version of distance-regular graphs. In this paper, we characterize all weakly distance-regular digraphs of diameter 2.

Combinatorics · Mathematics 2025-07-16 Xiangli Wang , Yuefeng Yang

Weakly distance-regular digraphs are a natural directed version of distance-regular graphs. In [16], we classified all commutative weakly distance-regular digraphs whose underlying graphs are Hamming graphs, folded n-cubes, or Doob graphs.…

Combinatorics · Mathematics 2024-08-07 Qing Zeng , Yuefeng Yang , Kaishun Wang

A weakly distance-regular digraph is quasi-thin if the maximum value of its intersection numbers is 2. In this paper, we show that the valency of any commutative quasi-thin weakly distance-regular digraph is at most 6.

Combinatorics · Mathematics 2016-09-20 Yuefeng Yang , Benjian Lv , Kaishun Wang

In this paper, we classify commutative weakly distance-regular digraphs of valency 3 with girth more than 2 and one type of arcs. Combining [8, Theorem 1.2], [10, Theorem 1.3] and [11, Theorem 1], commutative weakly distanceregular digraphs…

Combinatorics · Mathematics 2017-11-07 Yuefeng Yang , Benjian Lv , Kaishun Wang

In this paper, we classify all commutative weakly distance-regular digraphs of girth $g$ and one type of arcs under the assumption that $p_{(1,g-1),(1,g-1)}^{(2,g-2)}\geq k_{1,g-1}-2$. In consequence, we recover [13, Theorem 1.1] as a…

Combinatorics · Mathematics 2021-08-03 Yushuang Fan , Zhiqi Wang , Yuefeng Yang

A digraph is semicomplete if any two vertices are connected by at least one arc and is locally semicomplete if the out-neighbourhood (resp. in-neighbourhood) of any vertex induces a semicomplete digraph. In this paper, we characterize all…

Combinatorics · Mathematics 2024-09-12 Yuefeng Yang , Shuang Li , Kaishun Wang

We classify certain non-symmetric commutative association schemes. As an application, we determine all the primitive weakly distance-regular circulant digraphs.

Combinatorics · Mathematics 2019-08-26 Akihiro Munemasa , Kaishun Wang , Yuefeng Yang

Suzuki (2004) [7] classified thin weakly distance-regular digraphs and pro- posed the project to classify weakly distance-regular digraphs of valency 3. The case of girth 2 was classified by the third author (2004) [9] under the assumption…

Combinatorics · Mathematics 2016-10-31 Yuefeng Yang , Benjian Lv , Kaishun Wang

A digraph is semicomplete multipartite if its underlying graph is a complete multipartite graph. As a special case of semicomplete multipartite digraphs, J{\o}rgensen et al. \cite{JG14} initiated the study of doubly regular team…

Combinatorics · Mathematics 2025-01-22 Shuang Li , Yuefeng Yang , Kaishun Wang

Strongly regular graphs are highly symmetrical and can be described fully with just a few parameters yet the existence of many of them is still under the question. Due to this uncertainty, it is of immense interest to study their structure,…

Combinatorics · Mathematics 2025-11-05 Reimbay Reimbayev

A graph is {\em $1$-planar} if it can be drawn in the plane such that every edge crosses at most one other edge. A connected graph $H$ is {\em strongly light} in a family of graphs $\mathfrak{G}$, if there exists a constant $\lambda$, such…

Combinatorics · Mathematics 2018-11-20 Tao Wang

A graph is $\ell$-reconstructible if it is determined by its multiset of induced subgraphs obtained by deleting $\ell$ vertices. We prove that strongly regular graphs with at least six vertices are $2$-reconstructible.

Combinatorics · Mathematics 2022-10-24 Douglas B. West , Xuding Zhu

We classify certain non-symmetric commutative association schemes. As an application, we determine all the weakly distance-regular circulants of one type of arcs by using Schur rings. We also give the classification of primitive weakly…

Combinatorics · Mathematics 2023-07-25 Akihiro Munemasa , Kaishun Wang , Yuefeng Yang , Wenying Zhu

Distance-regular graphs are a class of regualr graphs with pretty combinatorial symmetry. In 2007, Miklavi\v{c} and Poto\v{c}nik proposed the problem of charaterizing distance-regular Cayley graphs, which can be viewed as a natural…

Combinatorics · Mathematics 2023-11-15 Xueyi Huang , Lu Lu , Xiongfeng Zhan

Weak degeneracy of a graph is a variation of degeneracy that has a close relationship to many graph coloring parameters. In this article, we prove that planar graphs with distance of $3$-cycles at least 2 and no cycles of lengths $5, 6, 7$…

Combinatorics · Mathematics 2025-02-26 Tao Wang , Ya-Nan Wang , Xiaojing Yang
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