It follows from the results of , Gyirfis and Lehel (1985), and Kostochka (1988) that 4 ~x\* ## ~5 where x\* = max {X(G): G is a triangle-free circle graph}. We show that X\* ? 5 and thus X\* = 5. This disproves the conjecture of Karapetyan that X\* = 4 and answers negatively a question of Gyirfis
Triangles in a complete chromatic graph with three colors
β Scribed by A.W Goodman
- Publisher
- Elsevier Science
- Year
- 1985
- Tongue
- English
- Weight
- 556 KB
- Volume
- 57
- Category
- Article
- ISSN
- 0012-365X
No coin nor oath required. For personal study only.
β¦ Synopsis
Let Kr~ be the complete graph on N vertices, and assume that each edge is assigned precisly one of three possible colors. An old and difficult problem is to find the minimum number of monochromatic triangles as a function of N. We are not able to solve this problem, but we can give sharp bounds for certain combinations of the number of triangles of various kinds. These sharp bounds are related to the main problem, and may be of independent interest.
π SIMILAR VOLUMES
## Abstract Let __C__ be the class of triangleβfree graphs with maximum degree at most three. A lower bound for the number of edges in a graph of __C__ is derived in terms of the number of vertices and the independence. Several classes of graphs for which this bound is attained are given. As coroll
Let G be a triangle-free, loopless graph with maximum degree three. We display a polynomi$ algorithm which returns a bipartite subgraph of G containing at least 5 of the edges of G. Furthermore, we characterize the dodecahedron and the Petersen graph as the only 3-regular, triangle-free, loopless, c
We give an example of circuit chasing on a distance-regular graph which has triangles. In particular, we show that the number of columns \(\left(c_{i}, a_{i}, b_{i}\right)=(2,2 a, e)\) in the intersection array of a distance-regular graph is at most 1 , if all the preceding columns are \((1, a, b)\)
A simple polynomial-time algorithm is presented which computes independent sets of guaranteed size in connected triangle-free noncubic graphs with maximum degree 3. Let nand m denote the number of vertices and edges, respectively, and let c '= m/n denote the edge density where c < 3/2. The algorithm