Forcing spanning subgraphs via Ore type conditions
نویسندگان
چکیده
We determine an Ore type condition that allows the embedding of 3-colourable bounded degree graphs of sublinear bandwidth: For all ∆, γ > 0 there are β, n0 > 0 such that for all n ≥ n0 the following holds. Let G = (V,E) and H be n-vertex graphs such that H is 3-colourable, has maximum degree ∆(H) ≤ ∆ and bandwidth bw(H) ≤ βn, and G satisfies deg(u) + deg(v) ≥ ( 3 + γ)n for all uv / ∈ E. Then G contains a copy of H. This improves on the Bollobás-Komlós conjecture for 3-chromatic graphs proven by Böttcher, Schacht, and Taraz [J. Combin. Theory, Ser. B, 98(4), 752–777, 2008] and applies a result of Kierstaed and Kostochka [J. Comb. Theory, Ser. B, 98(1), 226–234, 2008] about the existence of spanning triangle factors under Ore type conditions.
منابع مشابه
Ore-type conditions implying 2-factors consisting of short cycles
For every graph G, let σ2(G) = min{d(x)+ d(y) : xy 6∈ E(G)}. The main result of the paper says that everyn-vertex graphGwithσ2(G) ≥ 4n 3 −1 contains each spanning subgraphH all whose components are isomorphic to graphs in {K1, K2, C3, K 4 , C + 5 }. This generalizes the earlier results of Justesen, Enomoto, andWang, and is a step towards an Ore-type analogue of the Bollobás–Eldridge–Catlin Conj...
متن کاملA Class of Orientation-Invariant Yao-type Subgraphs of a Unit Disk Graph
We introduce a generalization of the Yao graph where the cones used are adaptively centered on a set of nearest neighbors for each node, thus creating a directed or undirected spanning subgraph of a given unit disk graph (UDG). We also permit the apex of the cones to be positioned anywhere along the line segment between the node and its nearest neighbor, leading to a class of Yao-type subgraphs...
متن کاملDistribution of certain sparse spanning subgraphs in random graphs
We describe a general approach of determining the distribution of spanning subgraphs in the random graph G(n, p). In particular, we determine the distribution of spanning subgraphs of certain given degree sequences, which is a generalisation of the d-factors, of spanning trianglefree subgraphs, of (directed) Hamilton cycles and of spanning subgraphs that are isomorphic to a collection of vertex...
متن کاملWeighted enumeration of spanning subgraphs with degree constraints
The Heilmann-Lieb Theorem on (univariate) matching polynomials states that the polynomial ∑ k mk(G)y k has only real nonpositive zeros, in which mk(G) is the number of k-edge matchings of a graph G. There is a stronger multivariate version of this theorem. We provide a general method by which “theorems of Heilmann-Lieb type” can be proved for a wide variety of polynomials attached to the graph ...
متن کاملGenerating k-Vertex Connected Spanning Subgraphs and k-Edge Connected Spanning Subgraphs
We show that k-vertex connected spanning subgraphs of a given graph can be generated in incremental polynomial time for any fixed k. We also show that generating k-edge connected spanning subgraphs, where k is part of the input, can be done in incremental polynomial time. These results are based on properties of minimally k-connected graphs which might be of independent interest.
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Electronic Notes in Discrete Mathematics
دوره 34 شماره
صفحات -
تاریخ انتشار 2009