Separating path systems

We study separating systems of the edges of a graph where each member of the separating system is a path. We conjecture that every $n$-vertex graph admits a separating path system of size $O(n)$ and prove this in certain interesting special cases. In particular, we establish this conjecture for random graphs and graphs with linear minimum degree. We also obtain tight bounds on the size of a minimal separating path system in the case of trees.Comment: 21 pages, fixed misprints, Journal of Combinatoric

Sublinear expanders and their applications

In this survey we aim to give a comprehensive overview of results using sublinear expanders. The term sublinear expanders refers to a variety of definitions of expanders, which typically are defined to be graphs $G$ such that every not-too-small and not-too-large set of vertices $U$ has neighbourhood of size at least $\alpha |U|$, where $\alpha$ is a function of $n$ and $|U|$. This is in contrast with linear expanders, where $\alpha$ is typically a constant. :We will briefly describe proof ideas of some of the results mentioned here, as well as related open problems.Comment: 39 pages, 15 figures. This survey will appear in `Surveys in Combinatorics 2024' (the proceedings of the 30th British Combinatorial Conference