Intermediate strong cop numbers in connected vertex-transitive graphs

Determine whether there exists a connected vertex-transitive graph G whose strong cop number satisfies \(\scop(G)\notin\{1,\infty\}\).

Background

The paper studies weak and strong cop numbers for infinite graphs. Its main theorem proves that every vertex-transitive graph containing a thick end has infinite weak cop number, and the resulting corollary shows that every connected vertex-transitive graph has weak cop number either 1 or infinity. Thus, the weak-cop-number alternative in the explicitly posed disjunctive question is resolved negatively by the paper.

The corresponding issue for the strong cop number is not resolved: the paper does not establish that every connected vertex-transitive graph has strong cop number 1 or infinity, nor does it provide a graph with an intermediate finite strong cop number. The unresolved problem is therefore to determine whether such a graph exists.

References

The following question is one of the main open problems concerning weak and strong cop numbers, first stated in Question L, and reiterated for the special case of Cayley graphs in Question K and Question 1. Is there a connected vertex transitive graph $G$ for which $\wcop(G) \notin {1,\infty}$ or $\scop(G) \notin {1,\infty}$?

On weak cop numbers of transitive graphs  (2502.19724 - Lehner, 27 Feb 2025) in Introduction, Question 1