3 problems

For any integer $k\ge 2$, let $f(k)$ be the supremum of ${\rm fvs}(D)/|V(D)|$ over all orgraphs $D$ with maximum degree at most $k$, where ${\rm fvs}(D)$ denotes the minimum feedba…

For any integer $k\ge 2$, let $f(k)$ be the supremum of ${\rm fvs}(D)/|V(D)|$ over all orgraphs $D$ with maximum degree at most $k$, where ${\rm fvs}(D)$ denotes the minimum feedba…

A Steiner triple system on $n$ vertices is a 3-uniform hypergraph in which every pair of vertices is contained in exactly one edge. A hypertree is a connected, simple 3-uniform hyp…