Xiangxiang Liu

activity

20162025

most citedOrdering of bicyclic graphs by matching energy

7 citations · 17 across the 7 of their papers we have counts for

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7 papers · 1 filter

math.CO2025

Constrained Ramsey numbers for rainbow $P_{5}$

Xihe Li, Xiangxiang Liu

For any graph $H$ , let $R_{k} (H)$ denote the minimum integer $n$ such that in every $k$ -edge-coloring of $K_{n}$ , there is a monochromatic copy of $H$ . Given two graphs $H$ and $G$ ,…

math.CO2021★ 5 cited

On a conjecture of Nikiforov involving a spectral radius condition for a graph to contain all trees

Xiangxiang Liu, Hajo Broersma, Ligong Wang

We partly confirm a Brualdi-Solheid-Turán type conjecture due to Nikiforov, which is a spectral radius analogue of the well-known Erdős-Sós Conjecture that any tree of order $t$ is…

math.CO2021★ 4 cited

Spectral radius conditions for the existence of all subtrees of diameter at most four

Xiangxiang Liu, Hajo Broersma, Ligong Wang

Let $μ (G)$ denote the spectral radius of a graph $G$ . We partly confirm a conjecture due to Nikiforov, which is a spectral radius analogue of the well-known Erdős-Sós Conjecture th…

math.CO2018

The unicyclic graphs with the second smallest normalized Laplacian eigenvalue no less than $1 - \frac{6}{3}$

Weige Xi, Ligong Wang, Xiangxiang Liu +2

Let $λ_{2} (G)$ be the second smallest normalized Laplacian eigenvalue of a graph $G$ . In this paper, we determine all unicyclic graphs of order $n \geq 21$ with $λ_{2}(G)\geq 1-\frac…

math.CO2017★ 7 cited

Ordering of bicyclic graphs by matching energy

Xiangxiang Liu, Ligong Wang, Peng Xiao

Let $G$ be a simple graph of order $n$ and $μ_{1}, μ_{2}, \dots, μ_{n}$ be the roots of its matching polynomial. The matching energy is defined as the sum $\sum_{i = 1}^{n} ∣ μ_{i} ∣$ , wh…

math.CO2017★ 1 cited

Edge Connectivity, Packing Spanning Trees, and Eigenvalues of Graphs

Cunxiang Duan, Ligong Wang, Xiangxiang Liu

Let $G$ be the set of simple graphs (or multigraphs) $G$ such that for each $G \in G$ there exists at least two non-empty disjoint proper subsets $V_{1},V_{2}\s…

math.CO2016

Minimal Skew energy of oriented bicyclic graphs with a given diameter

Xiangxiang Liu, Ligong Wang

Let $S (G^{σ})$ be the skew-adjacency matrix of the oriented graph $G^{σ}$ , which is obtained from a simple undirected graph $G$ by assigning an orientation $σ$ to each of its edges. Th…