Ramsey sequences with bounded clique size

Abstract: A sequence of graphs ${G_k}$ is a Ramsey sequence if for every positive integer $k$, the graph $G_k$ is a proper subgraph of $G_{k+1}$, and there exists an integer $n > k$ such that every red-blue coloring of $G_n$ contains a monochromatic copy of $G_k$. Among the wide range of open problems in Ramsey theory, an interesting open question is ``Does there exist an ascending sequence ${G_k}$ with $\lim_{k \to \infty} \chi(G_k) = \infty$ and $\lim_{k \to \infty} \omega(G_k) \neq \infty$ that is a Ramsey sequence?". In this paper, we solve this problem by constructing a Ramsey sequence ${G_k}$ with a bounded clique number such that $\lim_{k \to \infty} \chi(G_k) = \infty$. Furthermore, using the observation that any monotonic increasing sequence of graphs that contains a Ramsey sequence as a subgraph is also Ramsey, we can generate infinitely many Ramsey sequences using this example.