Exact upper bounds for the minimum sizes of strong and weak separating path systems of cliques
George Kontogeorgiou, Maya Stein
TL;DR
This paper resolves tight additive upper bounds for separating path systems in complete graphs by a constructive prime-decomposition approach and a generating-path framework. It first builds a weakly separating path system of size $n+1$ on $K_n$ by partitioning $n$ into prime blocks and aggregating level-wise constructions, then enhances the system with eight auxiliary paths to achieve strong separation, yielding $ssp(K_n)≤ n+9$. The methods are explicit and modular, leveraging rotations and linear-forest arrangements to ensure separation across all edges. Overall, the results bring the weak and strong separation numbers of complete graphs closer to the conjectured $(1+o(1))n$ scale and provide concrete, implementable constructions.
Abstract
We prove an upper bound of $n+9$ for the strong separation number of the complete graph $K_n$, and an upper bound of $n+1$ for its weak separation number. This improves on the previous best known bound of $(1+o(1))n$ for both cases.
