On the Chudnovsky-Seymour-Sullivan Conjecture on Cycles in Triangle-free Digraphs (2009)
Chen, Kevin, Karson, Sean, Liu, Dan, Shen, Jian
For a simple digraph $G$ without directed triangles or digons, let $\beta(G)$ be the size of the smallest subset $X \subseteq E(G)$ such that $G\setminus X$ has no directed cycles, and let...