Let $G$ be a simple graph with $n$ vertices. Let $\omega(G)$ and $\chi(G)$ denotes the clique number and chromatic number of $G$ respectively. Then
Does $\omega(G)\leq k$ imply $\chi(G)\leq k$ for $n\geq 3$?
Let $G$ be a simple graph with $n$ vertices. Let $\omega(G)$ and $\chi(G)$ denotes the clique number and chromatic number of $G$ respectively. Then
Does $\omega(G)\leq k$ imply $\chi(G)\leq k$ for $n\geq 3$?
No, even triangle free graphs are counterexample since they can have arbitrary large chromatic number.
https://en.wikipedia.org/wiki/Triangle-free_graph#Coloring_triangle-free_graphs
No. For the cycle graph $C_5$, $\chi(C_5)=3$, but $\omega(C_5)=2$. So for $k=2$, $\omega(C_5) \le k$ but it is not true that $\chi(C_5) \le k$.