Edge-ordered Ramsey numbers of complete graphs
Determine whether the exponential lower bound for edge-ordered Ramsey numbers of arbitrarily ordered complete graphs K_n is tight.
References
For edge-ordered graphs, a major open question is to find a better estimate for edge-ordered Ramsey numbers of edge-ordered complete graphs on $n$ vertices. In particular, Fox and Li asked whether the exponential lower bound is tight for general edge-orderings of $K_n$.
— A Survey on Ordered Ramsey Numbers
(2502.02155 - Balko, 4 Feb 2025) in Section 4, paragraph beginning “For edge-ordered graphs, a major open question”