{ "id": "1507.08022", "version": "v1", "published": "2015-07-29T05:46:48.000Z", "updated": "2015-07-29T05:46:48.000Z", "title": "Expression for the Number of Spanning Trees of Line Graphs of Arbitrary Connected Graphs", "authors": [ "Fengming Dong", "Weigen Yan" ], "comment": "22 pages, 7 pages, presented at the National Conference of Combinatorics and Graph Theory at Guangzhou, China in Nov. 2015. It was submitted to JGT in Feb. 2014 and revised in July 2015", "categories": [ "math.CO" ], "abstract": "For any graph $G$, let $t(G)$ be the number of spanning trees of $G$, $L(G)$ be the line graph of $G$ and for any non-negative integer $r$, $S_r(G)$ be the graph obtained from $G$ by replacing each edge $e$ by a path of length $r+1$ connecting the two ends of $e$. In this paper we find a combinatorial approach to obtain %an expression for $t(L(G))$ and more generally an expression for $t(L(S_r(G)))$. Thus we generalize some known results on the relation between $t(L(G))$ and $t(G)$ and prove a conjecture that $t(L(S_1(G)))=k^{m+s-n-1}(k+2)^{m-n+1}t(G)$ for any graph $G$ of order $n+s$ and size $m+s$ in which $s$ vertices are of degree $1$ and the others are of degree $k$.", "revisions": [ { "version": "v1", "updated": "2015-07-29T05:46:48.000Z" } ], "analyses": { "keywords": [ "arbitrary connected graphs", "line graph", "spanning trees", "expression", "combinatorial approach" ], "tags": [ "conference paper" ], "note": { "typesetting": "TeX", "pages": 22, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2015arXiv150708022D" } } }