Abstract
A ρ-mean coloring of a graph is a coloring of the edges such that the average number of colors incident with each vertex is at most ρ. For a graph H and for p > 1, the mean Ramsey-Turán number RT(n, H, ρ-mean) is the maximum number of edges a ρ-mean colored graph with n vertices can have under the condition it does not have a monochromatic copy of H. It is conjectured that RT(n, Km, 2 - mean) = RT(n, Km, 2) where RT(n, H, k) is the maximum number of edges a k edge-colored graph with n vertices can have under the condition it does not have a monochromatic copy of H. We prove the conjecture holds for K3. We also prove that RT(n, H,ρ- mean) > RT(n, Kχ(H), p - mean) + o(n2). This result is tight for graphs H whose clique number equals their chromatic number. In particular, we get that if H is a 3-chromatic graph having a triangle then RT(n, H, 2- mean) = RT(n, K3, 2 - mean) + o(n2) = RT(n. K3. 2) + o(n2) = 0.4n2(1 + o(1)).
Original language | English |
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Pages (from-to) | 126-134 |
Number of pages | 9 |
Journal | Journal of Graph Theory |
Volume | 53 |
Issue number | 2 |
DOIs | |
State | Published - Oct 2006 |
Keywords
- Coloring
- Ramsey numbers
- Turan numbers
ASJC Scopus subject areas
- Geometry and Topology