Disjoint Chorded Cycles of the Same Length | SIAM Journal on Discrete Mathematics | Vol. 29, No. 2 | Society for Industrial and Applied Mathematics
نویسندگان
چکیده
Bollobás and Thomason showed that a multigraph of order n and size at least n+ c (c ≥ 1) contains a cycle of length at most 2( n/c + 1) log2 2c . We show in this paper that a multigraph (with no loop) of order n and minimum degree at least 5 contains a chorded cycle (a cycle with a chord) of length at most 300 log2 n. As an application of this result, we show that a graph of sufficiently large order with minimum degree at least 3k+8 contains k vertex-disjoint chorded cycles of the same length, which is analogous to Verstraëte’s result: A graph of sufficiently large order with minimum degree at least 2k contains k vertex-disjoint cycles of the same length.
منابع مشابه
Disjoint Chorded Cycles of the Same Length
Corrádi and Hajnal [1] showed that any graph of order at least 3k with minimum degree at least 2k contains k vertex-disjoint cycles. This minimum degree condition is sharp, because the complete bipartite graph K2k−1,n−2k+1 does not contain k vertex-disjoint cycles. About the existence of vertex-disjoint cycles of the same length, Thomassen [4] conjectured that the same minimum degree condition ...
متن کاملDisjoint chorded cycles in graphs
We propose the following conjecture to generalize results of Pósa and Corrádi Hajnal. Let r, s be nonnegative integers and let G be a graph with |V (G)| ≥ 3r + 4s and minimal degree δ(G) ≥ 2r + 3s. Then G contains a collection of r + s vertex disjoint cycles, s of them with a chord. We prove the conjecture for r = 0, s = 2 and for s = 1. The corresponding extremal problem, to find the minimum n...
متن کاملOn independent doubly chorded cycles
In a graph G, we say a cycle C : v1, v2, . . . , vk, v1 is chorded if its vertices induce an additional edge (chord) which is not an edge of the cycle. The cycle C is doubly chorded if there are at least two such chords. In this paper we show a sharp degree sum condition that implies the existence of k vertex disjoint doubly chorded cycles in a graph. © 2015 Elsevier B.V. All rights reserved.
متن کاملOn vertex disjoint cycles of different lengths in 3-regular digraphs
Henning and Yeo [SIAM J. Discrete Math. 26 (2012) 687–694] conjectured that a 3-regular digraph D contains two vertex disjoint directed cycles of different length if either D is of sufficiently large order or D is bipartite. In this paper, we disprove the first conjecture. Further, we give support for the second conjecture by proving that every bipartite 3-regular digraph, which either possesse...
متن کاملLargest Eigenvalue of the Laplacian Matrix: Its Eigenspace and Transitive Orientations | SIAM Journal on Discrete Mathematics | Vol. 30, No. 4 | Society for Industrial and Applied Mathematics
We study the eigenspace with largest eigenvalue of the Laplacian matrix of a simple graph. We find a surprising connection of this space with the theory of modular decomposition of Gallai, whereby eigenvectors can be used to discover modules. In the case of comparability graphs, eigenvectors are used to induce orientations of the graph, and the set of these induced orientations is shown to (rec...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2015