A directed graph $G^t$ is said to be a transitive reduction of the directed graph $G$ provided that (i) $G$ has a directed path from vertex $u$ to vertex $v$ if and only if $G$ has a directed path from vertex $u$ to vertex $v$, and (ii) there is no graph with fewer arcs than $G^t$ satisfying condition (i). The problem asks to find such a graph $G^t$ for a given digraph $G$.