Explicit Ramsey graphs and orthonormal labelings
Explicit Ramsey graphs and orthonormal labelings
复制标题
显式拉姆齐图和正交标记
DOI:
--
复制
发表时间:
1994
影响因子:
0.7
通讯作者:
N. Alon
中科院分区:
文献类型:
--
作者:
N. Alon
We describe an explicit construction of triangle-free graphs with no independent sets of size m and with ›(m 3=2 ) vertices, improving a sequence of previous constructions by various authors. As a byproduct we show that the maximum possible value of the Lovasz µ-function of a graph on n vertices with no independent set of size 3 is £(n 1=3 ), slightly improving a result of Kashin and Konyagin who showed that this maximum is at least ›(n 1=3 = logn) and at most O(n 1=3 ). Our results imply that the maximum possible Euclidean norm of a sum of n unit vectors in R n , so that among any three of them some two are orthogonal, is £(n 2=3 ).