Motivated by the work of Nešetřil and R ödl on "Partitions of vertices" we are interested in obtaining some quantitative extensions of their result. In particular, given a natural number r and a graph G of order m with odd girth g, we show the existence of a graph H with odd girth at least g and ord
Graphs without short odd cycles are nearly bipartite
✍ Scribed by Ervin Györi; Alexandr V Kostochka; Tomasz Łuczak
- Publisher
- Elsevier Science
- Year
- 1997
- Tongue
- English
- Weight
- 230 KB
- Volume
- 163
- Category
- Article
- ISSN
- 0012-365X
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✦ Synopsis
It is proved that for every constant ~ > 0 and every graph G on n vertices which contains no odd cycles of length smaller than ~n, G can be made bipartite by removing (15/~}ln(10/~)) vertices. This resuIt is best possible except for a constant factor. Moreover, it is shown that one can destroy all odd cycles in such a graph G alto by omitting not more thaa (200/e')0n(10/e)) z edges.
📜 SIMILAR VOLUMES
It is shown that any 4-chromatic graph on n vertices contains an odd cycle of length smaller than √ 8n.
Let H be a fixed graph. We show that any H-minor free graph G of high enough girth has circular chromatic number arbitrarily close to two. Equivalently, each such graph G admits a homomorphism to a large odd circuit. In particular, graphs of high girth and of bounded genus, or of bounded tree width,
## Abstract Let __G__ be a toroidal graph without cycles of a fixed length __k__, and χ~__l__~(__G__) the list chromatic number of __G__. We establish tight upper bounds of χ~__l__~(__G__) for the following values of __k__: © 2009 Wiley Periodicals, Inc. J Graph Theory 65: 1–15, 2010.
It is shown that there is a constant \(c\) such that if \(G\) is a graph embedded in a surface of genus \(g\) (either orientable or non-orientable) and the length of a shortest non-bounding cycle of \(G\) is at least \(c \log (g+1)\), then \(G\) is six-colorable. A similar result holds for three- an
## Abstract It is well known that every planar graph __G__ is 2‐colorable in such a way that no 3‐cycle of __G__ is monochromatic. In this paper, we prove that __G__ has a 2‐coloring such that no cycle of length 3 or 4 is monochromatic. The complete graph __K__~5~ does not admit such a coloring. On