19 Answers votes newest views recent 7Open problems with monetary rewards 50Identifying poisoned wines 34Is the empty graph a tree? 10Can assignment solve stable marriage? 6A “rewiring process” on graphs 9Erdős-Szekeres for first differences 12A graph with few edges everywhere 6How to keep subsets disjoint? 6Maximal number of directed edges in suitable simple graphs on $n$ vertices without directed triangles. 4union of regular polygons 4Cauchy-Davenport strengthening? 74-coloring maps of pentagons 5Red-blue alternating Menger’s theorem 10Induced Paths of Order 4 3Most inconsistent ranking 5Flow on Infinite Graphs 4Upper bounds on number of vertices of graphs whose complements has no induced cycles of certain lengths 3Stability of medians in Median graphs 4Maximum number of edges $f(n,k)$ in a graph on $n$ vertices with no $k$-core?