We prove that every graph of minimum degree at least r and girth at least 186 contains a subdivision of K rΓΎ1 and that for r5435 a girth of at least 15 suffices. This implies that the conjecture of Haj ! o os that every graph of chromatic number at least r contains a subdivision of K r (which is fal
Compact topological minors in graphs
β Scribed by Tao Jiang
- Publisher
- John Wiley and Sons
- Year
- 2010
- Tongue
- English
- Weight
- 155 KB
- Volume
- 67
- Category
- Article
- ISSN
- 0364-9024
No coin nor oath required. For personal study only.
β¦ Synopsis
Let be a real number such that 0< < 1 2 and t a positive integer. Let n be a sufficiently large positive integer as a function of t and . We show that every n-vertex graph with at least n 1+ edges contains a subdivision of K t in which each edge of K t is subdivided less than 10 / times. This refines the main result in [A. Kostochka and Pyber, Combinatorica 8 (1988), 83-86] and resolves an open question raised there. We also pose some questions.
π SIMILAR VOLUMES
A graph H is a minor of a graph G if H can be obtained from a subgraph of G by contracting edges. Let t 1 be an integer, and let G be a graph on n vertices with no minor isomorphic to K t+1 . Kostochka conjectures that there exists a constant c=c(t) independent of G such that the complement of G has
## Abstract It is shown that every sufficiently large almostβ5βconnected nonβplanar graph contains a minor isomorphic to an arbitrarily large graph from one of six families of graphs. The graphs in these families are also almostβ5βconnected, by which we mean that they are 4βconnected and all 4βsepa