Trivial colors in colorings of Kneser graphs
Résumé
We show that any proper coloring of a Kneser graph $KG_{n,k}$ with $n-2k+2$ colors contains a trivial color (i.e., a color consisting of sets that all contain a fixed element), provided $n>(2+\epsilon)k^2$, where $\epsilon\to 0$ as $k\to \infty$. This bound is essentially tight.