{ "id": "1904.06527", "version": "v1", "published": "2019-04-13T11:14:21.000Z", "updated": "2019-04-13T11:14:21.000Z", "title": "On the $g$-extra connectivity of graphs", "authors": [ "Zhao Wang", "Yaping Mao", "Sun-Yuan Hsieh" ], "comment": "20 pages; 2 figures", "categories": [ "math.CO" ], "abstract": "Connectivity and diagnosability are two important parameters for the fault tolerant of an interconnection network $G$. In 1996, F\\`{a}brega and Fiol proposed the $g$-extra connectivity of $G$. A subset of vertices $S$ is said to be a \\emph{cutset} if $G-S$ is not connected. A cutset $S$ is called an \\emph{$R_g$-cutset}, where $g$ is a non-negative integer, if every component of $G-S$ has at least $g+1$ vertices. If $G$ has at least one $R_g$-cutset, the \\emph{$g$-extra connectivity} of $G$, denoted by $\\kappa_g(G)$, is then defined as the minimum cardinality over all $R_g$-cutsets of $G$. In this paper, we first obtain the exact values of $g$-extra connectivity of some special graphs. Next, we show that $1\\leq \\kappa_g(G)\\leq n-2g-2$ for $0\\leq g\\leq \\left\\lfloor \\frac{n-3}{2}\\right\\rfloor$, and graphs with $\\kappa_g(G)=1,2,3$ and trees with $\\kappa_g(T_n)=n-2g-2$ are characterized, respectively. In the end, we get the three extremal results for the $g$-extra connectivity.", "revisions": [ { "version": "v1", "updated": "2019-04-13T11:14:21.000Z" } ], "analyses": { "keywords": [ "extra connectivity", "interconnection network", "extremal results", "important parameters", "fault tolerant" ], "note": { "typesetting": "TeX", "pages": 20, "language": "en", "license": "arXiv", "status": "editable" } } }