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Some upper bounds for the signless Laplacian spectral radius of digraphs | ||
| Transactions on Combinatorics | ||
| مقاله 20، دوره 8، شماره 4، اسفند 2019، صفحه 49-60 اصل مقاله (804.34 K) | ||
| نوع مقاله: Research Paper | ||
| شناسه دیجیتال (DOI): 10.22108/toc.2019.105894.1515 | ||
| نویسندگان | ||
| Weige Xi1؛ Ligong Wang* 2 | ||
| 1Department of Applied Mathematics, School of Science, Northwestern Polytechnical University, Xi'an, Shaanxi 710072, P.R.China | ||
| 2Northwestern Polytechnical University | ||
| چکیده | ||
| Let $G=(V(G),E(G))$ be a digraph without loops and multiarcs, where $V(G)=\{v_1,v_2,$ $\ldots,v_n\}$ and $E(G)$ are the vertex set and the arc set of $G$, respectively. Let $d_i^{+}$ be the outdegree of the vertex $v_i$. Let $A(G)$ be the adjacency matrix of $G$ and $D(G)=\textrm{diag}(d_1^{+},d_2^{+},\ldots,d_n^{+})$ be the diagonal matrix with outdegrees of the vertices of $G$. Then we call $Q(G)=D(G)+A(G)$ the signless Laplacian matrix of $G$. The spectral radius of $Q(G)$ is called the signless Laplacian spectral radius of $G$, denoted by $q(G)$. In this paper, some upper bounds for $q(G)$ are obtained. Furthermore, some upper bounds on $q(G)$ involving outdegrees and the average 2-outdegrees of the vertices of $G$ are also derived. | ||
| کلیدواژه‌ها | ||
| Digraph؛ Signless Laplacian spectral radius؛ Upper bounds | ||
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آمار تعداد مشاهده مقاله: 287 تعداد دریافت فایل اصل مقاله: 205 |
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