## Abstract Let __f__(__n__) be the minimum number of colors required to color the edges of __K~n,n~__ such that every copy of __K__~3,3~ receives at least three colors on its edges. We prove that $$(0.62+o(1))\sqrt{n}< \, f(n)< \, (1+o(1))\sqrt{n}$$, where the upper bound is obtained by an expli
Colorful induced subgraphs
โ Scribed by H.A. Kierstead; W.T. Trotter
- Publisher
- Elsevier Science
- Year
- 1992
- Tongue
- English
- Weight
- 302 KB
- Volume
- 101
- Category
- Article
- ISSN
- 0012-365X
No coin nor oath required. For personal study only.
โฆ Synopsis
A colored graph is a graph whose vertices have been properly, though not necessarily optimally colored, with integers. Colored graphs have a natural orientation in which edges are directed from the end point with smaller color to the end point with larger color. A subgraph of a colored graph is colorful if each of its vertices has a distinct color. We prove that there exists a function f (k, n) such that for any colored graph G, if x(G) > f (w(G), n) then G induces either a colorful out directed star with n leaves or a colorful directed path on n vertices. We also show that this result would be false if either alternative was omitted. Our results provide a solution to Problem 115. Discrete Math. 79.
๐ SIMILAR VOLUMES
## Abstract A lower bound is established on the number of edges in a maximum __k__โcolorable subgraph of a loopless graph __G__. For the special case of 3โregular graphs, lower bounds are also determined on the maximum number of edges in a bipartite subgraph whose color classes are of equal size.
## Abstract Given a โforbidden graphโ __F__ and an integer __k__, an __Fโavoiding kโcoloring__ of a graph __G__ is a __k__โcoloring of the vertices of __G__ such that no maximal __F__โfree subgraph of __G__ is monochromatic. The __Fโavoiding chromatic number__ __ac__~__F__~(__G__) is the smallest i