This work studies super-Ramanujan graphs: \(d\)-regular graphs whose spectral expansion lies strictly below the Ramanujan threshold \(2\sqrt{d-1}\). Although this threshold is asymptotically optimal for fixed \(d\) as \(n\) tends to infinity, it leaves open the finer question of how small the spectral expansion can be as a joint function of ... more >>>

The recent paper \cite{chatterjee2026bipartite} showed that deciding whether a bipartite graph has a perfect matching can be reduced to deciding whether a determinant, whose value may be assigned to any sufficiently large field $\mathbb{F}$, equals to zero. In the second part of their work, \cite{chatterjee2026bipartite} also generalized the algebraic method ... more >>>

In this note, we introduce the notion of ranked spreadness, a strengthening of the usual spread condition in which the elements of each member can be ordered so that their one-coordinate marginals decay geometrically with their rank. This additional structure removes the dependence on the maximum set size in random-containment ... more >>>