منابع مشابه
Edge Disjoint Paths in Moderately Connected Graphs
We study the Edge Disjoint Paths (EDP) problem in undirected graphs: Given a graph G with n nodes and a set T of pairs of terminals, connect as many terminal pairs as possible using paths that are mutually edge disjoint. This leads to a variety of classic NP-complete problems, for which approximability is not well understood. We show a polylogarithmic approximation algorithm for the undirected ...
متن کاملMinimally (k, k-1)-edge-connected graphs
For an interger l > 1, the l-edge-connectivity λl(G) of G is defined to be the smallest number of edges whose removal leaves a graph with at least l components, if |V (G)| ≥ l; and λl(G) = |V (G)| if |V (G)| ≤ l. A graph G is (k, l)-edge-connected if the l-edge-connectivity of G is at least k. A sufficient and necessary condition for G to be minimally (k, k − 1)-edgeconnected is obtained in the...
متن کاملEdge bounds in nonhamiltonian k-connected graphs
Let G be a k-connected graph of order n with |E(G)|>(n−k 2 )+ k2. Then for (k = 1, n 3), (k = 2, n 10), and (k = 3, n 16), G is hamiltonian. The bounds are tight and for k = 1, (k = 2, n 12), and (k = 3, n 18) the extremal graphs are unique. A general bound will also be given for the number of edges in a nonhamiltonian k-connected graph, but the bound is not tight. © 2006 Elsevier B.V. All righ...
متن کاملOn critically k-edge-connected graphs
Let G be a simple graph on n vertices having edge-connectivity /(.' (G) > a and minimum degree o(G) We say G is k-critical if /(.' (G) = k and /(.' (G e) < k for every edge e of G. In this paper we prove that a k-critical graph has 1<' (G) o(G). We descri be a number of classes of k-cri tical graphs and consider the problem of determining the edge-maximal ones.
متن کاملThe characterization of edge-maximal critically k-edge connected graphs
Let G be a simple graph on n vertices having edge-connectivity 1(' (G) > O. We say G is k-critical if 1(' (G) :::: k and 1(1 (G-e) < k for every edge e of G. We denote by ~(n,k) the set of all k-critical graphs on n vertices. In this paper we prove that the maximum number of edges of a graph G in ~(n,k) to be: k(n-k) if n ~ 3k; and L ~ (n+k)2 J. if k + 1 s n < 3k. Further, we characterise the e...
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ژورنال
عنوان ژورنال: Journal of Combinatorial Theory, Series B
سال: 1988
ISSN: 0095-8956
DOI: 10.1016/0095-8956(88)90077-9