Extending the idea from the recent paper by Carbonero, Hompe, Moore, and Spirkl, for every function $f\colon\mathbb{N}\to\mathbb{N}$ we construct a $\chi$-bounded hereditary class of graphs $\mathcal{C}$ with the property that for every integer $n\ge 2$ there is a graph in $\mathcal{C}$ with clique number at most $n$ and chromatic number at least $f(n)$. In particular, this proves that there are hereditary classes of graphs that are $\chi$-bounded but not polynomially $\chi$-bounded.
翻译:扩展了Carbonero、Hompe、Moore和Spirkl最近一篇由Carbonero、Hompe、Moore和Spirkl撰写的论文中的想法, 每一个函数 $f\ croom\ mathbb{N ⁇ to\mathb{N} 我们建造了一个由$\chi$约束的世袭类图 $\ mathcal{C}, 其属性是每整数$n\ge 2$, 就有以$\ mathcal{C} 的图表, 俱乐部数量最多为$n, 染色体数量至少为$f(n) 。 特别是, 这证明有些世系类图表是按$绑定的, 但不是按聚苯基$绑定的。