Yurui Tang

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20242026

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10 papers · 1 filter

math.CO2026

Nonhamiltonian regular sublinear expanders

Chengli Li, Yurui Tang

Letzter, Methuku and Sudakov proved that sufficiently regular sublinear expanders contain nearly spanning cycles and paths. Montgomery subsequently conjectured that every regular s…

math.CO2026

Characterizing forbidden induced subgraphs that force top vertices to be Gallai vertices

Yurui Tang

A vertex of a graph is called a top vertex if it has maximum degree in the graph. A vertex of a graph is called a Gallai vertex if it belongs to every longest path of the graph. Go…

math.CO2026

Weakly pancyclic vertices in dense nonbipartite graphs

Yurui Tang, Xingzhi Zhan

Let $G$ be a graph of girth $g$ and circumference $c .$ A vertex $v$ of $G$ is called weakly pancyclic if $v$ lies on an $ℓ$ -cycle for every integer $ℓ$ with $g \leq ℓ \leq c .$ …

math.CO2025

Extending two results on hamiltonian graphs involving the bipartite-hole-number

Kun Cheng, Yurui Tang

The bipartite-hole-number of a graph $G$ , denoted by $α (G)$ , is the minimum number $k$ such that there exist positive integers $s$ and $t$ with $s + t = k + 1$ with the propert…

math.CO2025

The circumference of a graph with given minimum degree and clique number

Na Chen, Yurui Tang

The circumference denoted by $c (G)$ of a graph $G$ is the length of its longest cycle. Let $δ (G)$ and $ω (G)$ denote the minimum degree and the clique number of a graph $G$ , respect…

math.CO2025

Cycles and paths through vertices whose degrees are at least the bipartite-hole-number

Chengli Li, Feng Liu, Yurui Tang

The bipartite-hole-number of a graph $G$ , denoted by $α (G)$ , is the minimum integer $k$ such that there exist positive integers $s$ and $t$ with $s + t = k + 1$ , satisfyi…

math.CO2025

The minimum size of a $k$ -connected locally nonforesty graph

Chengli Li, Yurui Tang, Xingzhi Zhan

A local subgraph of a graph is the subgraph induced by the neighborhood of a vertex. Thus a graph of order $n$ has $n$ local subgraphs. A graph $G$ is called locally nonforesty if…

math.CO2024

Sparse graphs with an independent or foresty minimum vertex cut

Kun Cheng, Yurui Tang, Xingzhi Zhan

A connected graph is called fragile if it contains an independent vertex cut. In 2002 Chen and Yu proved that every connected graph of order $n$ and size at most $2 n - 4$ is fragile,…

math.CO2024

The minimum size of a $3$ -connected locally nonforesty graph

Chengli Li, Yurui Tang, Xingzhi Zhan

A local subgraph of a graph is the subgraph induced by the neighborhood of a vertex. Thus a graph of order $n$ has $n$ local subgraphs. A graph $G$ is called locally nonforesty if…

math.CO2024

The maximum number of cliques in graphs with given fractional matching number and minimum degree

Chengli Li, Yurui Tang

Recently, Ma, Qian and Shi determined the maximum size of an $n$ -vertex graph with given fractional matching number $s$ and maximum degree at most $d$ . Motivated by this result, we…

Nonhamiltonian regular sublinear expanders

Characterizing forbidden induced subgraphs that force top vertices to be Gallai vertices

Weakly pancyclic vertices in dense nonbipartite graphs

Extending two results on hamiltonian graphs involving the bipartite-hole-number

The circumference of a graph with given minimum degree and clique number

Cycles and paths through vertices whose degrees are at least the bipartite-hole-number

The minimum size of a k-connected locally nonforesty graph

Sparse graphs with an independent or foresty minimum vertex cut

The minimum size of a 3-connected locally nonforesty graph

The maximum number of cliques in graphs with given fractional matching number and minimum degree

The minimum size of a $k$ -connected locally nonforesty graph

The minimum size of a $3$ -connected locally nonforesty graph