On the distance signless Laplacian spectral radius, fractional matching and factors of graphs
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| Format: | Preprint |
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2025
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| _version_ | 1866913848080990208 |
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| author | Zhang, Z. H. Wang, L. G. |
| author_facet | Zhang, Z. H. Wang, L. G. |
| contents | The distance signless Laplacian matrix of a graph $G$ is define as $Q(G)=$Tr$(G)+D(G)$, where Tr$(G)$ and $D(G)$ are the diagonal matrix of vertex transmissions and the distance matrix of $G$, respectively. Denote by $E_G(v)$ the set of all edges incident to a vertex $v$ in $G$. A fractional matching of a graph $G$ is a function $f:E(G) \rightarrow [0,1]$ such that $\sum_{e\in E_G(v)} f(e)\leq 1$ for every vertex $v\in V(G)$. The fractional matching number $μ_f(G)$ of a graph $G$ is the maximum value of $ \sum_{e\in E(G)} f(e)$ over all fractional matchings. Given subgraphs $H_1, H_2,...,H_k$ of $G$, a $\{H_1, H_2,...,H_k\}$-factor of $G$ is a spanning subgraph $F$ in which each connected component is isomorphic to one of $H_1, H_2,...,H_k$. In this paper, we establish a upper bound for the distance signless Laplacian spectral radius of a graph $G$ of order $n$ to guarantee that $μ_f(G)> \frac{n-k}{2}$, where $1\leq k<n$ is an integer. Besides, we also provide a sufficient condition based on distance signless Laplacian spectral radius to guarantee the existence of a $\{K_2,\{C_k\}\}$-factor in a graph, where $k \geq 3$ is an integer. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2505_13863 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | On the distance signless Laplacian spectral radius, fractional matching and factors of graphs Zhang, Z. H. Wang, L. G. Combinatorics 05C50 (Primary) 05C35 (Secondary) G.2.2 The distance signless Laplacian matrix of a graph $G$ is define as $Q(G)=$Tr$(G)+D(G)$, where Tr$(G)$ and $D(G)$ are the diagonal matrix of vertex transmissions and the distance matrix of $G$, respectively. Denote by $E_G(v)$ the set of all edges incident to a vertex $v$ in $G$. A fractional matching of a graph $G$ is a function $f:E(G) \rightarrow [0,1]$ such that $\sum_{e\in E_G(v)} f(e)\leq 1$ for every vertex $v\in V(G)$. The fractional matching number $μ_f(G)$ of a graph $G$ is the maximum value of $ \sum_{e\in E(G)} f(e)$ over all fractional matchings. Given subgraphs $H_1, H_2,...,H_k$ of $G$, a $\{H_1, H_2,...,H_k\}$-factor of $G$ is a spanning subgraph $F$ in which each connected component is isomorphic to one of $H_1, H_2,...,H_k$. In this paper, we establish a upper bound for the distance signless Laplacian spectral radius of a graph $G$ of order $n$ to guarantee that $μ_f(G)> \frac{n-k}{2}$, where $1\leq k<n$ is an integer. Besides, we also provide a sufficient condition based on distance signless Laplacian spectral radius to guarantee the existence of a $\{K_2,\{C_k\}\}$-factor in a graph, where $k \geq 3$ is an integer. |
| title | On the distance signless Laplacian spectral radius, fractional matching and factors of graphs |
| topic | Combinatorics 05C50 (Primary) 05C35 (Secondary) G.2.2 |
| url | https://arxiv.org/abs/2505.13863 |